We ran one of those road-side vegatable stands in Maine as well. We would be in the field harvesting and the stand was by honor system. The customers would weigh their own produce and count their own corn, cukes, etc. And then the customer would put the money into a box that could have been easily pilfered. Now that was in the ‘80s but we still run the campfire wood the same way on the side of the road.
A few times in the summer someone will take without paying but I still pray God would bless them. We took off with 20 bundles on the stand in the morning and returned after dark. All bundles of wood ($2.50/bundle) were sold and $50 was in the glass jar. No one took from the unattended glass jar. It does still happen in rural Maine.
Why are you no longer selling vegetables? I bought the best blueberries I’ve ever had from that guy in R.I. He had some damn good tomatoes, too.