As the others have noted, you won't see any pin trading on a regular ABD trip. However, if you do Back Stage Magic (or the new FL version) there is the regular pin trading in the parks during your off time. Similarly, if you add ABD to one of your DCL cruises there will be pin trading on board - again during your off time.
You should also be aware that you will get a new pin every day of your ABD trip. Everybody gets the same pins so there's really no interest in trading with anybody else for those.