score:6
You need to remove the permit from the windshield, which needs to be turned in, and carry it with you. Customs wants it back to refund the deposit and they will not let you get a new permit if you have not turned in an old one.
If the car is involved in a accident and is a total loss it is best to remove the permit from the windshield. If the car is stolen the insurance company needs to provide you with a letter that the car is gone, stolen, or totaled, and provide that letter to customs with claim information ... to get the deposit back; And, to allow you to get permits in the future.
This comes from the claims department of Instant Mexico Auto Insurance