Never had any problems with pins in my carry-on. Most of the time the X-ray machine can't see enough so I do have to go to the side and open the bag and let them inspect it.
I've found it easiest to put all the pins ( mine and my 2 DSs ) in one carry-on and make sure I'm the one associated with that bag so only one of us and only one bag needs to be searched seperately.
With the pin event coming up at disney I think security will be seeing alot of pins over the next few weeks so they should be very used to it
Rob