Your position inside the gym means jack shit. It's all about using proximity data and location data over time to make really, really spookily accurate guesses about people.
I wasn't arguing that you can't. I was responding to an earlier poster that was paranoid about being able to tell proximity with other users, so that they could tell that you were "with" someone. In that scenario, your position inside the gym is extremely important.
While strength != distance, if I'm "x dB" today and "x dB" tomorrow and so on for 10 days, on most of those days I'm probably in about the same spot.
That's not true at all. I've only found that to be true if I'm testing inside a faraday cage inside a controlled lab. Your signal strength will vary depending on what is between you and the AP, so if the people around you are different everyday, your readings will be varied. Even if those were constrained, your signal strength will vary depending on humidity and signal population density. You can probably get a nice average, if I monitor the data for 10 days. But if you are only inside starbucks for 10 minutes/day to grab a coffee, that is not enough time to build out something like that.
No reason at all why this couldn't be done. It's a single command on most Linux systems with a wireless card.
True, it's a single command. However, that command only works if the the chipset supports that feature, and if the driver supports going into that mode. Neither of these are true on all the phones I've tested.
but looking at who was near me every time I go to my favourite Starbucks over the course of a year will give you a pretty good idea of who is actually there with me.
Not really. I go to the gym everyday at the same time, and I see the same people there everyday... That is a coincidence that we have similar schedules... I am not in a relationship with any of those people I see regularly.
I have a set routine of what I do at the gym, as do most of the regulars I see regularly. For example, I may start on one side of the gym, and work my way to the other, and someone else may start at the opposite end, and work their way forward. It is entirely possible for both of us to maintain the same signal strength to the AP the entire time in relation to each other, simply because we are on opposite sides. There's no way to draw any conclusions from this data, other than we're both inside. You can try to write an app to figure out that we were standing next to each other the entire time, but that is a VERY complex problem to solve, and you aren't going to solve it by simply monitoring beacon packets.
Only God can make random selections.