I don't know about customs, but TSA will confiscate your DE blade. I flew with one a couple of times and got away with it, but I finally got busted. On a recent flight I took my Feather and mailed blades ahead. On another I just took a multi-blade razor and it went just fine. In reality, I get just as close a shave with my DE or with a multi-blade as I do with an SR more consistently, with less bother, faster, and with fewer nicks - but somehow it just isn't the same.