In California you need a license for anything you "attach, add, modify, or make an improvement to structurally" as it pertains to signs. Even putting vinyl on a window you need a license for if it adds up to over $500. If you sub it out to a contractor and you're not licensed it's still a violation.
I know, I sound like a broken record.
Merry Christmas everyone!
Now that I think about it further, can we still make money being completely legit with all bases covered as required and regulated?