So heres an interesting point:

1) No Twitter/FB integration. Yes, you want this NOT using your mobile data. You just need that msg sent ASAP with minimal overhead so that the message has the highest chance of getting out there. Also proably easier to implement.

2) If you are getting arrested, how will you turn on the phone, get to the app, open it, and long-hold the bullseye. This should be set up as part of a buddy system. O well... first steps and all i guess.

Cue a bunch of people being shot / tasered / gassed as they reach for their phones?