In case you're unfamiliar: https://people.howstuffworks.com/hobo-code.htm
There are so many chains and franchises in the restaurant world, it's impossible to keep up with which ones are worker-friendly. You can't just bust out and ask the barista how much they make – maybe you could, but that just makes everything awkward.
So, instead of that: A mark on the wall or pavement outside a place might mean “This place only pays minimum wage. Take your business elsewhere.” Another might indicate that the shop has unionized , etc.
Thoughts?