I do IT for the local offices (town and airport) of an international airline. I realize that this post was about things that got seized at security, so this is slightly tangential, but… The airport office is packed full of things that people tried to check in but that CANNOT go on a commercial airplane, checked or otherwise; in particular, I’ve seen well over two dozen sets of gas-filled shock absorbers.
I know, I know - the likelihood of one of those failing catastrophically in the cargo hold is pretty low (although the greater pressure differential makes it less unlikely), but the potential damage if it did happen makes my flesh creep. Who the hell would want to pack those things in his luggage and then FLY with them? I mean, sure, send them home with your cousin you never liked anyway…
More closely TSA-related, however - at least two of their passengers have tried to board with sword canes, which is pretty badass. I’d never actually seen a real-life sword cane before that.