I saw campus and thought it was a college. I was wondering how they could track two people out of all the people walking around on a college campus.

It's possible they could be out so late that they were the only two people around but I've been out really late (1 or 2 am) and there's still a few folks walking around.

Interesting that this high school also has a RADIUS type network that kids are allowed to access with their phones. Phones were strictly forbidden when I was in school and there was no wifi.

Google is doing similar things for law enforcement in the states. LE organizations will ask google for the data of everyone within a geographical area and they will sift through to arrest people (sometimes erroneously).