I got someone else's amenity in Hilton Prague Old Town once. The people in the the room that was assigned to me didn't check out on time so I was given another room. 2 seconds after I had entered the room, a bell-boy came running to remove the amenities (assortment of cakes, big bottle of sparkling water and some fruit, I think ). He realised that he couldn't carry it all so he went of to get a trolley. A few minutes later he came back looking embarassed and told me that reception had told him to leave it for me. He then rushed off and forgot to take the welcome card and letter. So I got diamond amenities instead of gold.