heh! that happened to me at Space last sunday!
we are in the main room for Sasha or Zabiela (forgot who was on).
i get a water and am walking up to the area behind the stage. some guy asks for a sip...being nice i say sure. then a girl reaches out for the bottle and i'm like okay, go ahead. then without asking, she hands it to some other guy she's with and i'm like wait a second! you guys drink 1/4 of my water and then start handing it around to others without asking? it wasn't a $ thing - just have some respect and ask if you can take a drink. the guy i took it back from gave me the evil eye and i'm like GFY!
yea, thats what happens when you give out your drink.. You are right, its not just a money thing, but times before when I DID give my bottle to someone, I never even got a thank you!