I'm Such an Idiom!

Idioms are interesting things, especially when you are dealing with a language that is not your primary one. For example, we were at a Mexican restaurant the other day, and the restaurant had several signs up explaining changes that had recently occurred. The signs all explained that they could not sell alcohol and said "thank you for your comprehension." I imagine that they were meaning thank you for your understanding and simply used another word that in most contexts would mean the same thing. Unfortunately, in this case it changed the meaning of the signs from "Thank you for supporting us despite this" to "Thank you for being able to wrap your puny mind around this. I know it's difficult to figure out such a complicated concept."