Here's how you screw with our prepuberty sups in this situation.
Fill a bottle with apple juice and tell'em you really have to go. If he says no, go get your bottle and poor it infront of him. You COULD get in trouble for it but never heard of anyone being in trouble for pouring out apple juice
I had one of those little punks tell me he wanted to 'take it across the street' with me. I was tempted to call the 800 # on'em but why bother? They don't get fired or relocated. They get told to say they're sorry and they'll never do it again...Maybe he wanted to buy me an ice cream?
I wish UPS would hire a young manager who's danglers have actually dropped (trying to come up with a new term for that is tough! Hope it doesn't get edited

). Or even better, sups who don't live with their mommy and daddy anymore. Maybe then they could get a grip on reality.