We had some great and frustrating experiences with pin trading at DLRP in 2005.
There didn't seem to be many Guests into pin trading, which seemed to make for better availability of attractive pins on the CM lanyards. We also had a great time trading pins with one Guest who seemed to be from the local area. We had tons of WDW pins which he'd never seen before, he had lots of DLRP pins which we'd never seen before, so everybody was very happy!
We also had a very unpleasant experience trading pins with a pin shark, who was sitting near the main hub. I know pin sharks show up everywhere, but the dynamics get trickier when you're not operating in your native language, especially with young kids involved.
All that being said....I'm gonna stock up on pins for trading on my next trip, as many of my most-treasured pins were traded for at DLRP.