dark tint on the back window is an Officer safety issue. CHP has to fill their quota each day also and tint tickets are easy to find and with the fine being raised this year its good for california.
Now, if you get a ticket and go to court to fight it you will have to apppear one tome and plead not guilty and ask for "OR" so you dont have to pay the fine before you leave. When you return a 2nd time if the Officer is in court, which most of the time he should be per Dept policy you can call him as a witness and ask questions. Remember now he is under oath. Ask him if he has tint on his personal vehicle. I can almost guarantee he does, if he lies it could cost him his job if he says yes, you can take it from there