Certain occupations, whether salaried or not, don't lend themselves to perfect OSHA compliant workplaces. For example, my dad was a pharma salesman -- salaried full-benefits position. He raised our entire family on that. He drove a lot. He never worked in an office. There was no 'designated' spot to pee. The times I would go on the road with him, we always went to gas stations, or restaurants. It would be better to have an app honestly.
Certainly it is difficult to find public bathrooms in American cities. That is not a problem with gig work though. It affects a lot of occupations, many of them white collar.