Apparently, the popularity of farmers' markets is just too much temptation for some unscrupulous vendors.
NBC Los Angeles' news team decided to do some checking around at local farmer's markets, and paid visits to the farms where the vendors claimed they grew the food they were selling. In some cases, they found fields full of weeds or dry, empty fields. The vendors were selling vegetables and fruit they had bought wholesale, and were selling it at premium prices at local farmer's markets, claiming it was locally grown and organic.
As to the "organic" claim, NBCLA also sent several items purchased from vendors who claimed not to use pesticides to labs for testing, and the results came back positive for pesticides. One of the "farmers" claimed that the pesticides found on their produce was the result of overspray from nearby farms, but the levels found on the tested produce were too high for it have been mere "drift."
This particular story was reported in California, but there's no doubt that it's happening all over the country. Near my home, for example, there is a "farmer's market" in a church parking lot every weekend during the summer. How they managed to have perfect-looking "locally grown" watermelons in early May in Detroit is beyond me. Needless to say, I don't shop there.