No, the vendors will not give you water under any circumstance, wristband or not, paid or not. You literally have to get soda, pour it out, and find a drinking fountain if you want to refill with water. And of course, the drinking fountain has low water pressure, so you're tilting the cup and lucky to fill it up halfway.

Does it matter who it comes from? Free water is available. The anti-American snipe of "Soda [is] easier and cheaper than plain good tasting water." is wrong.