That stinks!
I have to say though as a good dog owner who always picks up after her babies - the other day DH and I were walking the dogs and we were in a rush and didn't notice the baggie holder was out and needed a refill.
Well of course, Bentley decided to poop in the middle of the road, so I told my DH we'd need to grab a bag and walk back (we were only 5 houses from home).
The lady that lives in the house near the road came out YELLING at us to pick up after our dog.
Maybe she just didn't know that we ALWAYS do, but I was absolutely mortified by that because sometimes stuff just happens.
I would never run after someone who didn't pick up after their dog once.
If it was a recurring thing probably, or if it was in my yard -- but that lady totally embarrassed me and I find myself not even wanting to walk by her house now