Here's my point -
Would it be nice if every place had a public restroom? Yes.
Would it be nice if an employee at a location w/o a public restroom made an exception & let you use the employees' private restroom if you asked if you were sick, w/ a child who really had to go, etc.? Yes.
But sometimes situations are not always as nice as we would like for them to be.
We cannot assume that exceptions will always be made for us. We have to take responsibility for ourselves & for our children.
Is it okay to ask if you can use a "not-for-public-use" restroom? Absolutely.
However, if someone asks to use a private restroom facility & he/she is told, "No, I'm sorry," what then gives that person the right to start demanding an exception be made?
Why is it okay to make threats - "If you don't let me use the restroom, then I'm going to be sick all over your floor." "If you don't let my child use your restroom, then he's gonna pee all over your floor."
Why is it okay to say, "If my child did have an accident & the employee handed me cleaning supplies, I'd throw the cleaning supplies back at the employee"?
Why is it okay to continually berate & harangue & guilt someone (whoever - teacher, receptionist, cashier, server...) into giving you your way/what you want?
Is that how you would wish to be treated?
"If I do it for you, I have to do it for everyone."
"You don't have to do it for everyone. Just me. In my special situation."
I don't think that kind of attitude is very fair or kind.
We've all been in emergency situations. It's nice if exceptions are made, but you can't bank your life on exceptions always being made.
(And, yes, I have 3 children. And, yes, I know what "rural" is.)