I went to lunch with my 5 year old niece on Saturday. She was sitting at the end of the table. The waiter left a pitcher of water right in front of her. Then a while later nobody is paying attention to her and her hand is sort of wet. I think she was touching the ice cubes.
My sister was mad. I didn't think it was that big a deal. Kids are always touching the ice cubes in their own glasses. And while it would seem obvious not to stick your hand in a pitcher of water it might not be that obvious to a kid.
I had to tell the waiter to spill out the water so he didn't serve any other tables with it. He was actually very funny about it. He said, "oh yum, I'm going to go pour myself a glass right away."