Seems to me that we've spent our whole careers learning to be efficient (and many times in spite of the roadblocks management throws up). Every fast food place, convenience store, or truckstop that has self service soda fountains will let you fill up your own cup with ice for free and most every fountain has a little lever marked "water". Are you going to tell me I can't get a drink of water on the clock? Is there some difference between those and a drinking fountain at the hub?
Even if I were to be so bold and fill up with soda, I don't wait in line. I'd have exact change or throw a couple of bucks at the cashier and tell him to keep it. Hell, I do the same thing if I need a meal, toss $10 at the McD's cashier and say "Number 1 large with a coke etc" as you're walking by toward the restroom and you pick it up on your way out, letting them keep the change, without even breaking your stride.