@HepLaurenceLB ARGHHHHHHHHHHH! I AM SO WITH YOU!!!!!!!!!!!!!
Where I live (a village with around 500 people, and a couple of miles in length and width, from end to end,) I see dogshit on our footpaths at LEAST once or twice a week. I don't know when they do it, but I think it's mostly at night when they can't be seen.
Between my house and the one at the end of my road (some 100 yards/300 feet,) me and my neighbour counted SEVEN piles of dog shit the other week. We are sick of it.
I have trod in it a number of times, whilst putting the wheelie bin out, whilst walking down the road to the little shop, and whilst going out to trim the bushes outside in the summer. Several times I have dragged it into the house! 
I don't buy it that the dogs cannot help where they shit either, because they never EVER do it when me or DH (or any of our neighbours,) are stood at the top of our driveway watching them!
I see them stop, but the owner pulls them away, and they shoot off down the road. So they DON'T have to let the dog do it on the footpath. And anyway, why do they not pick it up with a pooper scooper, and bag it up and take it home?!
I saw someone suggest a few remedies (on here) to stop dogs shitting on the footpath near your house. I will see if I can find the thread. Or google it! Nothing to hurt the dogs (obvs!) but just something to 'deter' them.
And yeah it is horrible for people with pushchairs, and wheelchairs... And also elderly people, and people with limited eyesight. One woman (with limited eyesight,) who lives down my road told me a few weeks ago, that she steps in dog shit sometimes, and the stick she uses to help her walk, gets covered in it too. It's so vile. There are warning signs around the village, but it doesn't seem to stop people letting their dogs shit all over the footpaths.
Vile, inconsiderate, filthy pigs. If I catch them, I will hose the fuckers down where they stand! I NEVER seem to bastard catch them though!