A quick story. When I was 18 I could get into a casino cuz it was on a college campus so the age limit was 18. I met my dad there and he hit a royal flush on the video poker machine. It paid him 4 grand. He had to wait for the lady to come give him the cash, about 20 minutes. He then gave her 3 hundred bucks as a tip. I asked him why he gave her so much. His answer to me was simple "300 bucks to me is nothing, it could feed her family for a week". Ever since then I tip pretty well, I respect people who work for a living. Besides, would you really miss a buck?
That's very generous of your dad, but I still don't get why your dad would 'tip' the lady for giving him the money he WON.
I can see where tipping could come into play, but geezus, c'mon...
Are you gonna tip the garbage man for picking up your trash twice a week or whatever?