Hmmmmmmm. My Glock snaps into my Fobus securely and I can't see how, outside of a pretty good yank on the gun, it could come out. Both my holsters are like that.I love my Fobus but they are not very secure.....Look at Horseshoe Leather in the UK superb designs run by Andy Arratooian (sorry Andy I haven't spelt it right).......A one man band and holsters hand made for professionals
And you won't as long as you don't fall or get pushed onto your back. This is more of a problem for police who may carry a back up gun or are working undercover becuase their chance of getting into a scuffle are greater than your regular citizen, but if you get mugged or into a fight and land on your back, damage is likely to occur.I just use a Left-Handed, inside-the-pants holster. When you put a left handed holster in the middle of your back, it is spun around to where it's positioned for your right hand.
I have a small carry, and a big fat butt... and I've never had any problems with pressure on my spine.