I frequently drive 5-6 hours, I'll travel with a large size cup of ice, as it melts I'll drink the water.

There have been times where I've needed more ice so will stop into the store at the gas station when refilling. I'll fill up my personal cup with ice from the soda machine.
On more than one occaision, but thankfully not often, the store will attempt to charge me for the ice in my personal cup even though I'm buying a bottle of ice tea or other beverage. (I never try to simply refill my cup with ice without any purchase)

When I go to return the bottle beverage back to the cooler, the clerk inevitably says, don't worry about the ice charge. Gee Thanks.