First, the only likely way to make that trip with only one stop for gas is to do it in a car getting better than 40mpg, so unless they're in a good hybrid and haven't loaded it down too much, I'm pretty sure they're going to get gas twice.
Second, I don't know about you, but unless I'm dehydrated, I pee rather more often than once every six hours, and I definitely stop more often than that on the occasional ~800 mile road trip I take.
Assuming this game of telephone hasn't gone too badly awry, your friends are extreme outliers, not "a typical person in the US used to driving distances".
I replied in edit but said the wrong thing. Corrected version:
Edit reply: it's a few refills but each is quick and lasts shorter than a battery charge. Would estimate 5 minutes for human needs every 3-6 hours is reasonable. I don't believe this is unusual long-distance driving behavior. And again, I don't think Tesla should be judged right now on their ability to cater to that market; we should be looking at how well Tesla serves those driving a couple hundred miles or several hundred miles in a more leisurely fashion.
Second, I don't know about you, but unless I'm dehydrated, I pee rather more often than once every six hours, and I definitely stop more often than that on the occasional ~800 mile road trip I take.
Assuming this game of telephone hasn't gone too badly awry, your friends are extreme outliers, not "a typical person in the US used to driving distances".