Wow you get there early. Most of the vendors at ours are not there until later. And most I have seen know what they have. Not that I would know. Still working on the knowledge.
At my flea if you have a reserved space you have to get there by 6 a.m. If you don't check in they sell your space to a "daily" vendor who is lined up ready to get it !
There are about 250 or so vendors at my flea. I haven't broken it down percentage wise by vendor type specifically, but there are what I would call "garage/yard sale" vendors (like us), "wholesalers" who sell "made in China" new goods and toilet paper, and food or produce vendors. Of the garage sale vendors, many are hispanic, some black, most caucasian....within those ethnic groups there are people who represent all orders of intelligence with the bulk being average or below...that's where the money is to be made for those who know what to buy...the rest is just luck in getting there first with that knowledge.
The chief "picker" has 15,000 plus feedback on eBay (not me...I'm at about 850). He never stops at my booth as he knows I am competition and won't sell him anything cheap. He does not sell at the fleas.
The next picker has 6,000 plus feedback on ebay. He sells at the same flea I do and they both shop the other 3 fleas in our immediate area.
One of the guys who has sold for 8 years at my flea has just quit the flea (at least for a while) to do nothing but picking and he drives up to 90 miles to go to other fleas for picking...that's too much for me.
Anyway, picking seems to be working right now.