Very difficult for cash to not trade hands in any type of trade or at any show where there are buying and selling restrictions; close to impossible.

Any well-stocked dealer should not mind what goes on anywhere and anytime away from their table... There is no reason to complain for any reason, whatsoever... and, any dealer who does needs to not worry because buyers come well prepared to do just that; buy, buy and buy... as most well-stocked dealers are prepared to trade, trade and trade.

Very few folks on both sides of the table are not prepared.