I used to buy a cup of coffee at McD if I needed to use the bathroom. I might still if the line isn’t too long. The problem is when the street people end up using the restrooms ALL the time, and/or trashing them. We were at a hamburger joint in the city and the manager had to buzz you in to the one restroom. (The other one had been trashed).
As my elderly mom left the restroom, a homeless guy sprinted in behind her almost knocking her over to catch the closing door.