I have been at trade sessions for probably 15 or 20 years now and I can say that very rarely does a trader come in with the sole intention of selling their chips outright. Yes there are times that a trader has only $70 in chips to trade with the other party who has $75 in chips and has to find some way to make the deal work out so it is fair the both. That is the case of where a few current chips may be added to the pile. Most collectors have multiple duplicate chips and trading is a good way to add to your collection. Those same people are also the ones who are going into the convention room and spending money on the dealers chips. So long as a deal is fair, whether trade or purchase on the convention floor, the collector will be happy. Eliminating or curtailing the trade sessions may mean a lot fewer buyers on the convention floor and that is not what the dealers want.