Proof of workers comp is required to pull a permit, so we know you have it if you have a permit.
As for the certification that's a state requirement, we collect a fee for it, but that goes straight to the state to pay for them to enforce it. We do not enforce it and I know that many other jurisdictions do not enforce it. You may get an inspector from time to time that will check, but in reality he has no authority to do anything other than call the license board.
OK here's my take on it:
As mentioned WC is often asked about during filing for permitting in most every city, and often filed with EIN/SNN, business lic. for same city/town, etc. Granted you could lie, and say you don't need any, but assume they will check if you are sole owner.... As you can be exempt... (Like me when I do work under my own lic.)
I have never heard of an inspector saying anything else but checking 'certifications' is not their job, and it is not....
As for the CSLB it again is not their job either....
They do not even receive complaints for it! (from the average schmo) The process is: Someone whoever that might be, decides to make trouble for their competition, or whoever they want to make life hell for. They then fill in a form - they send it to the DAS, the DAS - if they feel like making trouble and they don't always, (There are some factors I won't mention) if they do.... They then send a "referral" to the CSLB once the DAS has "certified" there is a violation. If there is a violation of the certification laws - the CSLB then comes and opens the can of snakes and pours it all over you. (Be sure to where clean skives....) They then give you a punishment for the certification violation, as well as for anything else the snakes might find.... The punishment for the certification of employees is supposed to be "progressive" at first (fines so far) and will eventually mean they can 'Suspend or revoke" your C-10 - if you have one... If you don't the snakes will already sussed that out.....