Frying is probably a bad description. My guess is the SIM card gets locked (there are 3 different methods for this). You can also lose service if the MSISDN is set incorrectly. I've been running .37 for three days with no incident (except for UMA not working). I now have an updated firmware loaded and UMA works (although it doesn't seem to like the Tmo MyFaves app).

I doubt these cards are overheating or shorting out. If that is the case, then loading beta software is probably the least of your worries ;)