Ditto what was said above
I hate being the cynical one (maybe its because I'm back here in rainy, windy Chicago versus in WDW) but having worked with people in the law enforcement arena I unfortunately concur with what Jasper says, it really is a sad reflection of the times when people who are trained to create "magic" have to watch out for the same things that TSA screeners and sky-marshals have to watch for.
I had been tempted in the past to give gifts to the characters but my 1st visit back in 2005 I had chatted with a CM who told me the same thing that was told to the previous poster; "great idea, nice thought, but don't give anything irreplacable or expensive because 9 times out of 10 its going in the breakroom trash can because of post 9-11 security reasons"
Don't get me wrong I am a huge WDW fan and a bigger fan of the characters, and I also concur with what the poster said about not discouraging giving gifts but just keep in mind what was said...