I've had ASA 64 film fogged by x-rays, ESPECIALLY if you had it IN CAMERA at the time, I had terrible lines in one that I know specifically went through the scanner.
They are usually understanding and will probably "patt you down" just in case, and sometimes open the cardboard box part, but there is a rule/law, they can't x-ray it if you are firm.
However they can also be very difficult, it's best to either ship your film ahead by USPS or FedEx as they won't x-ray OR find a photo store ahead of time and pre-order so you can just pick it up when you get there.
The Noteworthy Ones - Mamiya: 7 II, RZ67 Pro II / Canon: 1V, AE-1 / Kodak: No 1 Pocket Autographic, No 1A Pocket Autographic
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