[nyxxie]

All this to get an app to make "do any of my contacts also use signal" requests? You could probably just figure out what endpoint the mobile client calls and imitate them yourself to avoid all the overhead of setting up the mobile devices. If you have to register to make the request, just provision a bunch of VOIP numbers and go to town.

Point being, if "who is using signal" is a question you want answered, it's far more trivial than having to acquire actual devices. Your oppressive regime could go from zero to black bag list in an afternoon.