He doesn’t have to tell anyone about the deadly traps (that are separate from the dungeon crawl) - they and the Stone are supposed to be secret. If Voldemort can’t even find them, so much the better.
Since he doesn’t admit publicly that there are deadly traps, his public justification of the dungeon crawl is the same no matter if there actually are traps or not.
He doesn’t have to tell anyone about the deadly traps (that are separate from the dungeon crawl) - they and the Stone are supposed to be secret. If Voldemort can’t even find them, so much the better.
Since he doesn’t admit publicly that there are deadly traps, his public justification of the dungeon crawl is the same no matter if there actually are traps or not.