"Try Shopping at the Local Supermarket ... "
As our research video (see below) demonstrates, there's no question that the plebian-friendly Safeway, serves up its produce with a heady dose of trademarks (some of which they market to third parties.) There are store brands, grower brands, and the ubiquitous PLU stickers. These stickers are intended to assist in tracking the produce, and often include a source trademark. (For those tired of peeling off stickers, get ready for tattooed pears.)
"The Ragged Sign Simply Says 'Farm Stand' ... "
We like your description of the farm stand sign. We can almost see it on the sun-dappled two-lane, right there with the Burma shave signs, and junior's handmade lemonade sign. But is it real or nostalgia? And anyway, if agra-business and local ordinances have not decimated the U.S. farm stand, there's probably a "stealth" trademark traveling with that ear of yellow stuff anyway (considering that 70% of the corn grown in the U.S. is GMO -- please Monsanto, don't sue; we promise to eat our vegetables!).