Ellenpoly - the correct treatment of these filthy antisocial bastards is to follow them with a plaggie bag in your hand, when the dog craps let it and its owner move off a little way, put your hand in the plaggie bag and pick the turd up, follow them at a discreet distance until they reach their home and have gone inside, then place the turd, nestling in the plaggie bag, on their doorstep and move smartly away to a suitable observation point (i.e one that offers concealment), throw a suitably-sized stone at their front door and wait and watch. Their expression on finding their own dog's shite nesting in a plaggie on their doorstep is priceless! :0) :0)

Johnny :0)

PS: It's good if you can run fast, in case you get spotted! :0)