Have similar experience with both dogs and cats. Quite a few years ago we moved into a house, got a couple of kittens which, like all moggies, took to wandering including into neighbours' gardens. A next door neighbour without our knowledge cut up some old tin cans and hammered them into their fence posts with the jagged edges of the cans sticking up which resulted in pretty severe cut paws for one of our kittens.
Needless to say we were livid, however I spoke in a civil manner to the neighbour who, credit where it's due, did apologise profusely, and removed the offending articles. After that we got on like a house on fire.
A more recent example involved our two present dogs about 6 years ago. Both are soft as butter Collies, we were across fields walking when loud shouting/screaming(playful) was heard from up ahead. Dogs were off the lead, dashed off immediately before I could do anything (slapped wrist pour moi ), and when I caught up a couple of fields later, there was this woman with her arms around her two kids (11/12 years old?) in a sort of 'cringing' fashon as if they were about to be ripped to bits by my two mutts who stood there, tails wagging, looking gormless.
What can you do??? I felt like giving the mother a good slap - she'd obviously instilled into her kids that all dogs were vicious - silly c*w.