I'm thinking about buying a bundle of pins off eBay for my upcoming trip. One of the listings I'm looking at has pins that it says are "100% tradeable at any of the Disney Parks." What has me wondering, though, is that it says "The posts are protected with the black rubber Mickey ears." I could be wrong, but I thought I had read somewhere that official pins had metal post protectors, not rubber. Am I mistaken; are the rubber backs valid? I'd hate to get to the park and not be able to trade anything!