I just attended an event at the American Enterprise Institute on "Big government and big food vs. food trucks, foodies, and farmers markets." One of the speakers is the founder of the Food Truck Association and one of the most popular food trucks in DC, Red Hook Lobster Pound. He spoke about the antiquated regulations in D.C. that treat food trucks as ice cream trucks. For instance, trucks aren't allowed to stay parked unless there is a line of people. DC officials say increased regulations on food trucks are about managing sidewalk congestion, but really it's a few members of the DC restaurant association urging DC officials to "level the playing field" for area restaurants.
Another panelist talked about regulations on farmers markets. Again, these regulations are not just overregulation by government officials, but officials working with interests who are against those hit hardest by the regulations. One example is an Ohio regulation that says farmers markets must have bathrooms and sinks for customers. Given that most customers aren't spending the day at the market, it's rather silly. I can imagine renting bathroom facilities for a few hours increases the booth cost for vendors and makes it harder for smaller vendors to participate. (Nevermind that even if there were Port-a-Pottys at a farmers market most of us would do all we could to avoid using them.)