Well, you never have to engage an external safety if you don't want to. As for the 1911s, AFAIK, most have inertial firing pins, so they will go off if dropped from some critical height. Most also have a half-cock safety to limit this, although the pin itself is still free to move and can still smack the primer if handled very roughly, even with the hammer not touching it.
I'm not a fan of cocked-and-locked, for my own part. I carry my single actions with one chambered, hammer at half-cock, safety off.