The best they can do is not allow you to bring certain items onto premises, but it doesn't mean they can just confiscate it. Not allow means they can tell you y

The best they can do is not allow you to bring certain items onto premises, but it doesn't mean they can just confiscate it. Not allow means they can tell you you can't enter with the item on your or that you have to leave the item with security to be stored and given back when you leave. This is standard practice with warehouses like that, they might not want you to bring things that could be mistaken for merchandise or could damage merchandise.