So, I live in a nice little neighborhood, and I try and keep my lawn looking nice and everything. So I have these local dog walkers (I suppose they live in my neighborhood somewhere). that always let their dogs piss and crap in my yard. Now they do clean up the crap, but I'm having a bit of an attitude about it. I'm not a pet owner myself, but am finding some resentment building up towards the pooch's. I should mention that I don't always see the offense, so I can't confront them.
How do I keep the dumb neighbors dogs from using my lawn as a public toilet?