Thanks for the '"welcome backs"! I've misses connecting with my poultry friends.
On the subject of buying and selling at shows and swaps, I've done both. You just have to be careful. The only swaps that I sell at are Milton and occasionally Knox, though it's a bit far. Both of those are casual about where you set up instead of having marked spaces crowded together, like at Wolf Lake. At Milton some other friends and I set up together, so we have our own little compound. I seldom buy at swaps unless I know or at least know about the seller or find something really special I'm also picky about who I sell to. I set my prices on the high end of reasonable and don't often come down unless I think the person is really deserving: example, I had 3 older hens that I considered stewpot ready. An older gentleman wanted to give them a chance and see if they might still lay a bit, so I cut him a deal.
At shows I prefer not to use the provided sale cages but to sell from my truck when allowed. One breeder that I know sends in entries for several large fowl double cages of the same breed, variety, etc. so they're all together. Then he marks them out for judging and puts his sale stock there rather than around the other sale birds. Generally the birds being sold at shows are from exhibitors so you can find a better quality and the sellers are pretty willing to talk to you about their stock. Still, caution is the keyword; check the bird carefully and quarantine. I like to treat my show and sale birds with gallimycin and vetrx for 3 days before, during, and after a show--doesn't always happen due to changing my mind about who's going at the last minute, etc. Martha Light in Kentucky bathes all of her sale silkies in addition to her show birds--she might have 100 sale birds there! She also has them color banded and tells what blood line they're from, etc.
'Nuff rambling--better go feed!