"At least 12 times" just jumped out at me. Since we've learned that the PCA provides just enough to be him arrested, I'm starting to think his phone may have been in that area a lot more than 12 times.
Yes, I also noticed that. One idea is that they have different types of data providing that info (cell tower use, wifi touches, gps - this is usually on even on airplane mode) and the PD only wanted to use the data that confirmed these 12 visits to the PCA or that they only used data provided by several/best sources for the PCA. The second option is that his phone was suspiciously turned off at some nights or that they just want to acknowledge that they don't know if he also visited the area without his phone.
I’m intrigued how one “picks up” wifi. You would need a password to be on the wifi. Or does this simply mean when the phone picks up the existence of all available close by networks without accessing them? Until now I didn’t know that this could be tracked.
A few threads ago, someone gave an excellent explanation of how that works. My admittedly non-techy summary is that the wifi and nearby devices exchange packets of data when they recognize and talk to each other, even the phone does not actually connect.
MOO: Yes. I am no expert, but the simplest logic is, that as you choose which wi-fi to connect to, you see a list of names. These names have not been inserted there by the manufacturers in China, right. So there is some sort of data exchange. The router says "Hello, stranger, I am KMEX-wi-fi and my general parameters are this and our signal strength is that". The phone says "Hello, stranger, I am BKs phone and my general parameters are this and our signal strength is that". This data is stored
somewhere for at least some time and accessible from both sides. Same with any turned on bluetooth device, imo.
Now, if he had his phone on airplane mode on any of the occasions, this might have still happened. In some phones, using airplane mode does not turn of the wi-fi at all! And I
think that I've read it a few times that this exchange happens even if you
have the wi-fi turned off, because it's like an automatic background process that the phone still does, maybe in order to show you the networks in a timely manner as you turn the wi-fi on. But the last part is pure speculation atm, as I will not start googling this again - but someone surely knows to confirm or deny this.