Did you ever order things like soap, cleaning sprays... anything that can leak?
On my last order they put almost every item, whether it could leak or not, in bags.
Oil, Realemon, Shampoo and the likes always go in bags, in addition to having the tops taped up.
Amazon puts shampoo in bags, but doesn't tape. I've got them to send me replacement shapoos a couple of times due to leaks (while keeping the leaked one).