Imaro
Legend
Scenario:
PCs are in a dungeon. They have searched it through and didn't find yet what they were looking for. But they found a chamber that's apparantly a teleportation device. They can't find any clues (because there are none) where it leads to, and eventually, they decide to risk it. The first character enters, and one after another, each of them decides to risk it.
I've seen this scenario in actual play and encounters. The reason why the entire party eventually risks is is because we know that it'S a game and we're the protagonists. Whatever happens will propel the story, even if it's tough.
Or so we believe. In fact, this teleportation chamber teleports the PCs directly above a pool of lava. THey all die.
So then it wasn't an inescapable death trap, it was a choice to take a potentially dangerous action without knowing anything about it's consequences or effects... yeah they die if that's what I originally designed the device to do (though I have to ask...why does this thing teleport over a pool of lava, this just seems arbitrary.).
Honestly, unless you agree to change this fact beforehand...It's a game where one of the assumptions is that one can "loose" by dying,, thus that should always be considered a possible consequence of one's actions.
I would say this fails the qualification for "real death trap".
Who is raising them? And isn't the reason why you get the party raised not just because it makes "sense" from a purely verisimilitude perspective, but because the "show must go on"?
But even if you do it, wouldn't it feel a little... shallow to the players? "We only survived because the DM said we should, and we only died in the first place because the DM said we would. No amount of "smart play" would have saved us or created our way out." (Smart Play it might be if the PCs ensured they have an ally that would raise them, or that have a "raise dead insurance" or a contingency spell cast on them. But is that something possible in every game world at every level?)
Uhm, notice I said if they take the precautions to make sure they get raised again the impetus is on the PC's to make sure they get raised... not me as the DM. And if this isn't possible, perhaps the PC's shouldn't be diving into devices they know nothing about and have no clue where they lead... at least until they can do some actual research on it. You see it's not inescapable, they can easily walk away... and the funny thing is only a player who is used to things always being tailored to them would think like you have described. Thus why I said earlier that the different styles do foster a different mentality in players and DM's.