What was the first guy selling? If he didn't have a water tap available, he wouldn't have been able to give you a cup of water. (And I doublt he'd give you a bottle of water for free)
Plus, the ice in the coolers they use for chilling the bottled beverages is not safe to be used for consumption. (MANY Guests ask them for cups of ice or just melted ice water from the coolers, and the CMs have to refuse.) Consumable ice is kept in separate holders and toted around in their own buckets, separate from the ones used for chilling bottles.
-Rob