See, you can't really blame them for not having the security down. Hackers always have the advantage since they use exploits people don't know. Once it's brought to light, it can be fixed. If it's not fixed quick, THEN I blame them. But, either way, if you have On-Star and someone steals your car, call them and they find your car. If you're using a cell to send a signal like an SMS message, I'm sure it'll leave a trace too which would end up leading back to you. So, all-in-all, sounds like it may not be the best idea to try.