I know what you mean. I've got BBS split rim wheels on my car that used to have neat little hexagonal dust caps with BBS embossed in the top of them.
They lasted about a year or so but eventually disappeared, no doubt doing their duty on some Chav's Fiesta.
It's not the value of the things that were nicked, it's just that it's such low level, petty thieving it really makes you wonder at peoples mentality