Thats ridiculous OP,
i know plenty people with gens above $100k. You think they are going to carry the warranty card with them? Heck they have watch boxes with a dozen of those gens. If we have to worry about proving our jewelry being gen every time we step in a plane or aboard a ship, we might as well go rep because there's a good chance they might confiscate it.
Sounds crazy to me.
i recently went on two Europe trips: one to UK/Holland and the other to Paris. I took three watches each time. One gen and two reps. I know the more than frown upon it but if you are an honest guy and there's no warrant out for you, I think you're more than ok.