I've never had a problem in the USA asking for a hand check. When questioned about worrying about ISO 400 film I just tell them 'but I shoot it at 1000, not 400, and stand develop in Rodinal' (True). Their eyes glaze over but they hand check, and are always quite polite when doing so. (I'm quite polite when asking too.) Rather unlike the lady in Frankfort security who asked me to turn on my Nikon F and I told her I couldn't.