I do NOT normally travel with water on board, since we tend to do full hook-ups. So my answer would be NO...as you could not flush.
Assuming an emergency situation. I may have been smart enough to fill the tank. In which case, we would barely have enough water to substain our needs...answer is still NO.
I spent the holiday just north of Miami. Made 3 deliveries in the Miami area on Tuesday, moved to just south of Jacksonville. Wednesday morning I crossed over to Gainesville, FL. By Wednesday afternoon I was crossing back over to I-95 for the coastal ride up to Philly.
Traffic stunk, lots of Florida plates heading north. I saw a few little naked butts (some boys just drop em to their ankles and left if fly). Quite a few heading to or from the woods. As well as the front and rear doors open with mom or dad standing by.
Once or twice....I even "check my tires" on an on/off ramp. I have an inevertor,fridge,tv, etc... on board, but no potty. Like those running, I pick a spot where I can as well. You may KNOW what I am doing...I don't really care.
Do what you have to do, in the situation you are in. Do NOT rely on others, and screw normal senses of decorum. Stuck in traffic...cover the best you can...let it fly.