I live in a town of about 30000 people. For the last 5 years I have gone to kmart on Thanksgiving day for their sale. The same two ladies have been at the front of the line with me every year. They are best friends and always let me go potty there.
On BF I fly solo, but I follow the rules I set for my 3yo: no drink after 6:30pm, potty as soon as you get up.
This holds me most times; I usually get a chance to pee about 10 or so. By then if you don't have it, you won't get it!