Striker fired guns need decent trigger disipline and you allways need to remember during training that there is absolutly no real world reason to be in a hurry to reholster your weapon.
You can't just throw a Glock or Xd back in its holster. Unless you like holes in your foot.
That said, they're perfectly safe. No amount of thrashing about will set them off unless you accidentally shove something in thier trigger. If its holstered its safe.
I saw a real funny aftermarket safety for a Glock. It goes on the trigger. Its a push button switch that locks the trigger safety out. As long as the saftey is set you can't pull the Glocks trigger back. It looks like the safety button on a Spyder paintball gun. The funny thing though is: you have to touch the trigger to turn on/off the safety! Kinda defeats the point.
Plenty of guns with safeties. M1911a1, M9, FN p45, HK Usp, Sig. Nothing wrong with safe action trigger stuff either if thats your thing.
All the guns with safeties can still usually be carried safely without the safety on.....within reason, they still aren't all of a sudden going to go off. The safety makes them safer, it still a gun. For example, a 1911 still needs its trigger pulled and its grip safety squeezed to go off. Not likely to happen inside a leather or kydex holster. Is it?