Swarmkeeper
Hero
Yeah, people in my games don't accidentally fall off the sides of mountains and die on the way to the dungeon, unless I've designed it so that getting to the dungeon is a major part of the adventure and falling off the mountain is the major dramatic consequence of that part of the adventure. (although they may well fall off the mountain and have to climb back up.)
On the other hand, If I've just told them straight-out that they can clearly see that the rickety bridge across the crevasse is far too messed up to cross and they'll have to find another way, and they decide to try it anyway...
Yes to this. Telegraphing dangers solves so many issues.
Oh, and to stay on point: I'm that DM that tries my best to telegraph dangers so the players feel they can make informed decisions for their PCs without feeling "gotcha'd".