The Baltimore City Paper has an interesting article titled "Locavore's Lament" in which Michelle Gienow expresses her dismay at discovering that not all the produce and fruit for sale at the Market is produced by the seller or sourced locally. In other words, at her Baltimore area Farmers' Markets there are sellers who are buying stuff wholesale just like Wal Mart and Albertson's and selling it under the homespun "Farmers' Market" banner.
Based on my experience, it's not nearly as big an issue in the Spokane area as it is there. But it is an issue nonetheless. One of the first Farmers' Market vocabulary words I learned was "high staller." When we were turning over rocks looking for vendors for the Millwood Market three years ago it seemed like everyone wanted to know if we were going to allow "high stallers." They explained to me that high stallers were vendors that were allowed to come into the market and sell wholesale goods alongside the farmer who had actually taken part in producing the market goods.
The Washington State Farmers' Market Association does allow for what they call "Resellers". They define this as follows;
The logic is that when farmers in Spokane don't have cherries someone could buy from farmers in Yakama area and fill in the gaps of offerings at a local market. It's a good concept but it get's a little tricky to enforce when a reseller is or isn't competing with local farmers selling directly to consumers. We don't allow high stallers are the Millwood Market.
Washington is a big enough producer of fruits and veggies that we don't have to worry too much about someone trying to sell California produce at our markets. But if you go to Pike Place market you may want to look closely. I noticed on a visit last year that someone was selling stuff with a California label on it.
By the way, "high staller" is maybe the first phrase I've come across that has no recognizable presence on Google.