The Holiday Inn Warsaw also had a similar sale, presumably because guests had been checking out with the shower robes.

This is by no means as low as it goes: From a bathroom notice at a Four Points Hotel (about as low as I'd like to go) in Cleveland, Ohio:

"All items in this room have been inventorized"

I don't remember the rest but it amounted to the hotel deducting the cost from your credit card if house keeping found anything missing.