Where I live, there are many small farms with farm stands doing the very same thing. The only thing is most of them have cameras. Other than that, there's usually no one tending the farm stand. They usualy allow you pay with cash, check and some electronic payment form. Sure, there is probably some "shrinkage", but nothing like having to pay someone to collect payments all day. I patronize a small farm and I text the owners what I want the day before I arrive and my stuff is already there waiting. I leave check and I'm done. In many ways, I like this.