I made a mistake. Yes, if the soda was inside a bottle, the vendor places it in a plastic bag but of a smaller size than the one pictured. They don't do it with beer though, it needs to be purchased as is with a bottle.
I haven't seen anyone yet being more creative when they drink alcohol. They just eventually make a fool of themselves when they get drunk. I think for added creativity, people turn to drugs and not to alcohol.
Maybe it's to generate more income? After all, it's a good marketing strategy. Instead of earning from just a single person, they will earn twice when another person enters the club.