Theo laid it all out, ticking points off on his fingers as he went. "Dumbledore practically announced the location of the hidden object by publicly declaring the third floor corridor on the right-hand side off limits to students. For some that’s practically an invitation to investigate. Hagrid has been too loose-lipped about it. We saw Snape with a possible bite injury at Halloween, so it’s not just students who can get through that pathetically simply locked door. And there aren’t any wards or physical barriers to stop anyone going there, like an Age Line or a Fidelius Charm. If he really wanted to hide it, he’d quietly put it in a warded container and bury it under the floorboards of his study, or something. So I think it’s a trap." He crossed his arms behind his head and leaned back in his chair, looking smug at their open-mouthed reactions to his revelation.