Good question. Far as I know they scrutinize *everything*. Even just canes.
I found it irritating and yet hilarious the TSA would put up such a bitch-fit over a novelty cane. The more I think about it the more I get the impression either they knew it was a famous person and wanted to get his autograph or the unusual size of the actor is what "warranted" the extra attention. I suppose the cane could double as a makeshift bludgeoning weapon but that'd be kind of pointless unless it was a desperate fending-off.
I've had some things stolen behind me (palm pilot, green laser pointer, gold dollar) or in the case of energy drinks, just plain taken away because they weren't allowed on the planes (probably to boost the sales of drinks on the flights). I had to throw a japan steel keychain pocket knife away b/c if I didn't and tried to take it through I'd have been arrested and charged with a felony.
Had some sentimental value.