Not where I am, they're not. Here everyone knows a dog belongs to someone, no need for collars and leashes. Dogs are free to roam, unless someone takes umbrage and poisons them.
Not everyone here has a property in which to keep a dog off the street, no fences, etc...making sure people know a dog belongs is enough. We feed each other's dogs when the owners can't, we make sure the dogs are aware that they belong to someone. No stray dogs here, except during breeding season then the local males make sure they know they're not welcome...