I hadn't heard this but even if that is the case I think you would still save a ton of money if you drink alot of water on your trip. I know we definitely do. We burn through all of our snack credits and then still end up spending alot of money on water....
There was a thread recently about the $5 charge for accepting water and the thinking was it was hit or miss whether or not you would get charged. I don't even think a particular resort was charging consistently more than others. The thread then degenerated into a "should Disney store your crockpot, fridge, stroller, or other stuff for free" thread and got off path.