Reminds me of a discotheque in my town some years ago. A successfull business was sold to a not-a-clue guy, who wanted to own a disco. He had enough money to buy it and run it for some time, then the problems set in. When people bought a beer, and left some of it in the bottle on the counter, the staff was instructed to take that bottle, and fill it up with another partially-consumed beer. A guest figured this out, bought a beer and a red soda, drank the beer, refilled the bottle with the red soda, and left.
The next guest, who ordered a beer and got 25 cl of red soda and 8 cl of beer wasn't quite satisfied, and made a big fuss about it. The discotheque closed a few days later, and the original owner bought it back for half the price he sold it for.
Note that danish 33 cl beer bottles are made from a distinct dark green glass. The bottles are recycled endlessly by all danish breweries.