Really, I agree, there should be at least some chance they would die from a trap.
I ran into a hidden electrical trap that did singe my sim from head to toe, much like the catacombs. But he didn't die.
I wish the tombs would reset at least for a different sim from the same town.
And Sims 3 + Swords + Demons would be definitely more awesome. The ultimate in gaming fun. *dreams*
I ran into my first mummy, and he was cool looking, but not as aggressive as I had hoped either. He actually cursed my sim, and then on the way back to town my game crashed before I thought to save it.... *sigh*