Just pee off the side!I'd like to get an RTT. My wife thinks they are overkill, but we have been caught in the rain camping many times.
The only downside I see would be getting up in the night to use the bathroom.
Just kidding. It is like anything else you just take care of business. I mean you could camp on the ground with the creepy crawlies, have an easy time relieving yourself or you can sleep in the penthouse suite and take a few more steps to the bathroom.
I personally prefer the creature comforts of sleeping in the air. It is all a matter of preference really.