I rented a car in TLV recently at hertz. The guy asked me for a letter from amex that the rental is covered. I told him c'mon you know it's covered you get this multiple times a day. He responded we need a picture for our records. When he was returned the letter when he was done I told him to save it for the next guy that doesn't have the letter.
He also told me if you don't have the letter with you you can email it afterwards.