I carried slow and fast films, repeatedly, through big international airports like Houston, LAX, Atlanta, Amsterdam, Dusseldorf, Cairo, Johannesburg, Seoul, Sao Paulo and small shabby airports like Foz do Iguassu and numerous eastern european places where they rarely see 1600 speed film, if ever. I never never ever had any problem with carry-on packed film being damaged by x-ray.
Last year i went for work+holiday from Amsterdam to Sao Paulo - Foz do Iguassu - Rio - Houston - San Diego and back through Houston to Amsterdam, that's 7 scans in a row at least but i remember somewhere it was double checked. NONE of the film had any problem, including color slides 64 to 400 iso and BW film incl tri-x pushed to 3200.
The US is not the place where i'd bother asking for hand inspection, especially with an eastern european look and passport; the security checkpoints are always overcrowded, the people way too serious (signs hanging saying "no jokes please"). I pulled it off once in a while in Amsterdam, though (maybe that was more like flirting with the security girls?)