I'll answer the OP's question (about traveling with a shaker), as opposed to making him or her feel bad about asking in the first place. I don't use one myself, but an excellent dive buddy of mine always has one. She has never had a problem flying with it.
She uses it sparingly, but she has been able to alert me to some interesting stuff on our dives together in this way. Probably got a bunch of good photos thanks to that second pair of eyes. Yes, my buddy skills are probably awful, since I don't spend the dive staring at my buddy.
It's not that loud, and it's clipped on to her chest D-ring. It's pretty simple to just grab it and give a little shake, as opposed to deploying your knife, waving it around behind your back and then re-sheathing it. I guess a bolt snap is a bit safer, but it's still something that you have to unclip, use and stow.
I know that noisemakers are up there with split fins and jacket BCs on this board, but if it's not that loud and it's not used too often, a shaker can be a useful bit of kit.