One time when I was in a club over there last time I just bought a bottle from the bar and then needed a leak. Left my full bottle on table and returned to find my bottle gone. The barman said I should have put a napkin over the top to signify to the waitress that it wasn't finished. I wasn't happy as it would have been obvious the bottle wasn't finished with.
Is it common practice to do this over there? I don't like taking a bottle into the toilets for hygenie reasons.

