ToME WikiI was on a FF (lost sword) quest, and I found a chest. On attempted disarming I fell through a trap door. I had sensed traps, so I am fairly certain that the trap was on the chest.
From a realism standpoint I feel that it is a bug.
FearofFours: Chests can be magically trapped - I personally don't view this as a bug. Maybe you gazed at the shiny interior and fell into the chest then down to the next level?
NeilStevens: Yay, one by one we'll get the bugs from the forum to the wiki!
GreyCat: I've changed tome_230_branch to disallow trap doors on chests, full stop. They can be carried down to a quest level and then triggered, so simply suppressing them from being generated on chests on quest levels isn't enough.