My uncle, one of the people that got me into this, has been straight shaving for decades. He also travels alot for work and brings a blade along all the time, this was one of the things he warned me about. He has actually been asked by customs to unpack his luggage to show it a few times, however it was never a problem since it is indeed a tool as mentioned before.

Only once it got confiscated, he was traveling from Tanzania back to Holland carrying a TI with imitiation ivory and the customs couldn't figure out if it was real or not Very shameful since it was a beautiful blade though.

So unless it's any exotic material or if you pack it with heroin I suppose you should be fine!