Shows area-for unwanted/used items - like Carvboot

After reading so many discussion with members with un wanted items, new & used, why can't we not set up a caravan boot sale at the shows. I am sure it could be arranged when they are planning the show, to offer an area for this to happen which we pay to set up.  I bet it would be packed.  

As it sounds like we all have items which we would like to take or to buy and this would be a great place to do it as you have like minded buyer walking around.  What other member thoughts?