My wife and I took a walk around the neighborhood one morning and came across this sign.
What this tells me is there's money to be made here. This homeowner had to make up their own sign which has all the appearances of a ransom letter. There is a market out there for these signs.
I must say though for the most part the dog owners in our little community are pretty good about picking up their dog's duty from people's yards. This is a practice that makes my wife cringe from the thought - reaching down with hand in plastic bag picking up a moist steamy loaf of dog poop. Our front yard has no grass to trigger a dog's bowel responses so we're spared the occasional miscreant that this homeowner obviously has had issues with in the past. But what we have observed is the dog walker dropping off their prize filled baggy into our trash can on trash day. Foul! I painted a message on the lid of our trash can - "No Dog Poop Bags Please".
Problem solved...so far.