Interesting predicament

Back story: have a location that provides day services for individuals with disabilities. Now they have a small fleet of transportation vehicles for their clients plus contracted out to at least 1 transportation company (mine) for a handful of clients. 

Now, I understand that the bathrooms aren't really open to the public to use, and with the contracted company(s): a) faces of those drivers and monitors change constantly, even from the morning drop off to the afternoon pickup. b) they aren't really their employees but what if you need to go. Especially if you're in a lineup queue (there's 5 vehicles both in front and behind you so you really can't pull out to go elsewhere and come back) and there's still quite a bit of time before your individual client comes out to go home?

Fortunately, I had been there enough that the inside staff knows me and said it was policy to not allow it and it was a one time deal. So moral, make sure you go way before you go get the clients.