There's a universal law concerning psychics, magicians, mediums, and every other class of supernatural/paranormal person: they are inexplicably drawn together by some invisible force. I call this force, borrowing a bit from other media as indicated in this page's image, "gravity." I find this to be true without fail! If you're at an event of 5000 other people and there's one other magician there, you will somehow end up encountering them. In the case of friendly/ally magicians, this is great. In the case of, er, enemy stand users, it's not so great.
To some extent it is possible to buffer this effect by suppressing one's aura. There are exceptions, and there are some who cannot do this at all against high enough level foes--I, for instance, retain a past life curse that takes the form of a massive beacon of four dimensional blinding white emitting from my frequency... there's no going undercover against somebody with an open third eye who is capable of 4D sight, in other words, but I'm able to guard against basically all lower level foes this way (unless I choose not to out of a sick desire to see what happens anyway, something I am all too prone to across all my lives). Regardless, though, these suppression techniques cannot fight against the pull of gravity--nothing can. They can merely help shield a magician from others finding their exact location, so one may be able to slip through a crowd undetected, for example... but the pull will remain, and magicians of an intermediate and above level should be able to feel it when in proximity even if they haven't found the exact source.
One time at Michaels, for instance, I felt the unmistakable pull of another magician in the vicinity, possibly more. Their energy signatures did not give me confidence they would be harmless to encounter, either. I was able to find them by following the pull--there were two, dressed rather blatantly in sorcerer attire, and were muttering about offensive spells to each other when I wandered by. They didn't even look my way, so the suppression seemed to have worked... but had they been high enough level in their third eye/4d abilities, I wouldn't have been so fortunate. Likewise if the store hadn't been crowded. If we'd been the only ones in there, there likely would have been some kind of magick fight, even if only by proxy via spirits, before I could get out of there with my damn magazine frame.
It's relatively simple (as spirit programming goes) to program a spirit to seek out this gravitational pull and scan the area for any major threats. It may not be as accurate or as perceptive as you, but it can scan a large area and many people much quicker. I'll often have a spirit do this, or even just stay activated near me on standby scanning for malicious energy signatures, and it's come in handy before. It's something I am not very good at yet but practice frequently, and I feel like such a technique, when fully trained and maxed out, would be pretty fucking awesome and perhaps even "broken." I'll sometimes even be able to follow it back to a specific person, and getting better at it all the time. The general feeling, though, is like a toned down version of the extreme "pressure" one feels when in the presence of an entity-level being. It's a slight "menacing menacing menacing" in the air, but just the undercurrent, unless one scans deeper.
When nothing successfully blocks perception on either side is where things get interesting. There's a hushed, nervous anticipation when you feel that connection, that spark. There's a moment where your auras overlap and your energy signatures acknowledge one another, and it's like having the rug pulled out from under you. There's always an awkwardness to it, too, a "who talks first" thing. Since there are far more adversarial and dangerous magicians than peaceful and heroic ones, there's a natural hesitancy to reveal too much. It becomes a subtle dance. A psychological showdown in the metaphorical discotheque. The most common approach for an opening gambit is voicing an observation of the opposing party as a compliment... preferably, one that can be shrugged off if the other is deemed dangerous or if you realize you've looked at the wrong person. Not "I see you're another stand user" and posing dramatically, but something like "nice tarot card shirt" or "cool rock around your neck."
I seriously have used the latter before when buying a protective stone at an antique mall--referred to the black tourmaline as "the badass obsidian looking rock" to suss out the cashier who I'd just felt the pull from and who immediately started asking questions and showing me occult insignia on their person as a test of sorts. I still don't know if they were friend or foe, but I can always tell when they're there at the same time I am because I feel that pull again. It can be exhausting, honestly. There's a constant underground game of psychological warfare and constant metaphysical vigilance when one is a magician. Sometimes it's made easy when somebody introduces themselves to you and outs themselves immediately as a magician, or--in some cases--reveals information to you about your past life that you already know is true immediately upon meeting you... laying it all out on the line and cutting to the chase.
The one situation I've personally encountered where that happened (the other magician using a direct statement of information about my past life as an opener) was, by the way, an attempted trap to lure me into an area filled with angry spirits. I played dumb and bluffed my way out of it only to later see the person who was convinced to go in my stead coming back weeping, bloodied, and visibly slashed all over by invisible assailants, poor girl. The fact that such a thing even happened should show why I put such importance on vigilance in both monitoring gravity and in navigating interactions with other magicians when "caught" cautiously, at least at first.
This also appears to be able to happen online, as well. I've found circumstance to lead me, through no clear existing logical path, to crossing paths and discussing magick with the one magician in a massive group, with no acknowledgement of it until one of us rips the band-aid off and calls the other out on it. This leads me to believe this phenomena is a side effect of chaos as opposed to something based on proximity, though its pull can be felt and tracked when at proximity. It's not just limited to people, either--spirits are drawn to magicians as well, as are unusual situations. I have found in my research and travels that nearly everybody who is involved in paranormal activities in their lives had supernatural experiences without trying to spawn them at some point, and continue to find themselves inexplicably placed in more of those situations as time goes on... while the average person, and the vast majority of people, will never have a single firsthand paranormal encounter in their lives. You're either encountering aliens and ghosts and wizards and spirits, or you're never going to experience any of it and will therefore honestly understandably think everybody who does is just LARPing or is hallucinating. (To be honest, I'd think I was too if it weren't for all the times I've had objectively provable results, and the myriad of times that I've had others with me who experienced the exact same things and could verify all my experiences--one such example later in this same article).
There's one other aspect of gravity I would be remiss to ignore. The powerful energetic sensation one gets from meeting another magician can easily draw people together romantically as well. I've actually never dated or even slept with somebody who wasn't in some way connected to the metaphysical world. It's not a universal thing--I'd have to be attracted to somebody to begin with for this to have a magnifying effect--but I've heard it described by the other magicians I've met and loved due to this effect over the years. The intermingling of auras and the metaphysical aspects this adds to intimacy can be a huge boon to magick but can also be addicting and lead one to stay in a situation that in every other way is undesirable. It's also kind of like how they say that once you do meth, no other drug will ever be enough again and you'll never feel truly happy again without it (disclaimer, I'm a stoner but I've never done meth and have zero desire to)... once you've had psychic intimacy, you'll never get a satisfactory experience from the equivalent you get from the uninitiated again. And trust me, that really narrows down your options.
Finally, there's an odd sensation that goes along with this--dream invasions from magicians one will meet in the future due to gravity. This happened to me when I was SMS invaded by the entity that would later kill my mentor (before being defeated with a support item of all things) and on several other occasions, including a dream where I met a woman with flaming red hair and glowing red eyes to match, told my friend about it, and then we both encountered her deep in a now-demolished surreal indoor flea market before watching her smile at us, turn a corner, and vanish into thin air. We just looked at each other, went "you saw that too, right?", searched the entire place in case she showed up again, and left absolutely baffled and amazed. He still brings that up! This also happens, even more frequently to be honest, with non-invasion dreams of a prophetic nature... I almost always encounter a magician in a dream somewhere, even if it's just a vision and not an actual connection to their etheric double and mindspace, before I encounter them in the physical plane. It's not always in a timely manner, though--and keeps me guessing for sure.