Hmm - actually I doubt they would be able to tell it wasn't me by touch - I can't tell it isn't me by touch (it's not a full prosthesis, just a partial to even me up). And in fact, call me brazen, but I don't have any problem whipping it out to show someone (although getting it back into position might be more difficult). I just don't want to be slowed down more than I need to be. If I put it in my carry-on, would I put it in my baggie or what?

On the whole I'd rather check it but, of course, I have to consider lost and damaged bags - it was on the expensive side, and I don't relish filling out an insurance form with the term "lost breast".