As mentioned by at least two posters, a chambered glock carried through the activities of daily life depends on a properly designed, quality holster. I was close enough to be sprayed with gravel when someone reholstering a glock hung the trigger on the edge of the holster. I fully assign ultimate blame to user error, but a poorly designed "golly gee wizz tacticool" holster did not help. Luckily in this case no one needed medical attention.
Everyone needs to know his limits. If a chambered round is outside that mans limits, let him be. Even if he is not ready for a quick draw type event, he is still better prepared than an unarmed person.
I was at a gun show once when a police officer was trying a new holster for his 10mm glock, he put a bullet through is femor right there in the middle of the gun show. Guns going off when I'm not wanting them to is something to be considered. That's also why you never point it at something your don't want to destroy. Sometimes that is hard, when you consider the multiple angles involved with shooting pool, you realize that unless you are over soft dirt stuff can still happen. That said, anyone who isn't being rude about it should be given a pass when suggesting safety recommendations. The last thing I would want is my CCW to shoot someone I did not mean to shoot, and that includes me.