Really?! That also happens in England?
'Fouling of the public footpath' is the #1 anti-social behaviour problem in the UK, and in congested cities like London, the problem is even worse as you can imagine. I have to walk about 150yrds to take my kids to school and have to dodge at least 10 heaps of slowing disolving dog crap on the way there.
Much as I love animals, I have come to the conclusion the dogs have no place in urban society. They do not have the space or facilities that they need and with ever increasing dog attacks on children, my opinion is that all dogs should be strictly licenced, chipped, and pre-requisites laid out to those who want to keep them in built up areas.