I agree with Thunder, some of you guys are WAY overthinking this. Your bags will get checked by airport security on the way out of the USA. THose guys are only concerned about the safety of the airplane. In checked bags they are looking for bombs or something else that may be dangerous to the plane. They will definitely see the weights, but if they go so far as to open the bag and do a search, once they convince themselves that it is not a bomb they won’t give a crap what it is. If they figure it out they will get a chuckle. The bib hanger will probably just slide right through.
If you carry it on the plane, your bag will definitely be X-rayed, might get searched and you might get asked. Probably best to avoid this and just check it.
You may also get inspected by customs going into the country. Again, once they are convinced it is not some kind of contraband or weaponry, they will not care what it is. My experience is that the chances of getting stopped in customs is low. I have been to South Korea and was not inspected.
If it is any consolation, I will be smuggling a pump into Russia tommorrow. If I wind up in a Moscow jail I will let you know.