The stickers are probably to identify them as hotel property if a staffer is found with one.

My first career was as a hotel manager, and I'm surprised that these things are still kicking around. When first introduced they were a disaster - expensive to buy and install and a mountain of paperwork in rebates. Guests pulling things out and putting them back while deciding what to have. Of course it all comes to a head at the worst possible time - with checkout lines snaking through the lobby.

I'm sure hotel managers still curse the fool whoever invented a minibar. Probably the most labour intensive and error prone operation in a hotel.

I've actually seen cases where a guest would drink a beer, full the bottle with water, recap it and put it back. It could be a month and 15-20 turnovers of the room before some poor sap reaches for his Molson's and thinks he's grabbed an American brew by mistake.