Yeah I don't think California is that unique... I remember New York having the same basic process. I design signs all over the country and it's pretty much the same process though some areas do not require a sign contractor license or deal with sign criteria.
I'm thinking most do not even review sign codes, permits and ordinances because they just want to make signs and make the quick sale.
What's my favorite line... "it's easier to ask for forgiveness than get permission?" in this state (and few others) forgiveness cost 10,000 bucks, refund of money, arrest and/or loss of contractors license.
It's not the sign shops problem the process is there, it's the business owners.
It's only a problem for the sign shop if they do not have the proper licensing.