Exactly. It would be like Universal Greeting time, the internet chat convention whereby whenever someone comes into chat it is "morning" and whenever someone leaves chat it is "evening."
It was invented to cut out the static caused by someone coming in and saying "good morning" and everyone else comparing relative time zones. But instead of comparing relative time zones, we all started explaining Universal Greeting Time over and over.
Instead of explaining "coup" (as used in this context) over and over for the entire lifespan of a coffee shop, better just get a different name.