Well, my mag mount has survived 3 roll overs and never came off of the vehicle. To each their own but I've been in the 2way radio business for 33 years and have seen police cars with mag mount antennas and have never heard of them being a danger.
I don't care if my paint gets scratched, I'll just squirt more rustoleum on it.
I also don't care if I can't talk to Timbucktoo and back so a little bit of loss isn't a problem. I just prefer to not drill holes in the roof and have something I can easily move out of the way when I'm working on stuff.