My Mom and I just got back from 7 nights on the Zenith to Bermuda. The first morning I was out on the back deck (grill area) and the water/soda fellow came around pushing his drink cart. I had an insulated cup in front of me. Anyway, he tried to sell me a bottle of water. I explained that it was water I had in my cup and I could get all the water and ice I wanted for free inside. We bantered back and forth about his bottled water being better than the free water. Every time I passed him after that he'd ask me if I was ready for some "good" water. The next day he came over again while I was sitting on the back deck. I asked him what his tip was on one of the big bottles of water. He replied that it was about $1. So......I told him that I was going to buy a big bottle of water from him and write in a $5 tip, which would cover what he'd make if I bought a bottle a day from him for the rest of the trip. So then he'd be able to just smile and wave when he saw me. He was surprised by my suggestion but every time I saw him after that he'd grin and wave. For me it was a fun way to handle my guilt over never buying from the soda person and for him it was a little less work to get that tip.