You still have to pay someone to issue the tickets and potentially to prosecute if need be. That can really get expensive. How do you prove that I have what you say I have on my property without trespassing?
When I was in Louisiana, this was a constant issue with DOG FIGHTING, let alone dog breeding. Federal crime. You have to have cause and a warrant to go on the property. No warrant, no convinction, no charges. In my experience, the dog fighters (yes, it was so common that I and most other dog people knew at least a few dog fighters, it was a powerless issue, even some zoo employees fought dogs) would have enough reason to suspect, and would move the dogs for a month to another site.
As for vets euthing at shelters....in the county my husband lives in, its gas chambers. pack the pets in, close the door, and start the gas. Don't need a vet for that. They don't even check to be certain the pets are dead coming out of the chamber. They also don't check for microchips before or after euthanizing (which is states law), and a 3 day hold is all that is required. Oh, and if your neighbor takes your dog, turns it in as thier own, it can be euthed immediatly there. Reporting repeatedly hasn't done anything to affect any of that.
Having said that, the vet I work for doesn't euth for convenience. We refer to breed rescues.