Usually I'm against Justi, but that is kinda bullshit. That would be almost no advantage, and no one would even use it anyway in fear of losing an rare item. Someone on a power trip seen it and decided to be an ass hole. Lets be real here...
Not only that, you have no way of telling what's even in the damn crates without manually looking so your threats are invalid unless someone admits having it. You took advantage of someone trying to sell a rare item and screwed them over. Good job Mr. Admin.