A very recent anecdote to throw into the conversation.
We were cruising on our boat and became aware of shouts and screams on the towpath. As we drew nearer (there were moored boats there so we were chugging very slowly ) we realised the commotion was coming from a woman stood on the towpath with her leashed dog. An unleashed dog was approaching them, it's intentions / nature obviously unknown to her and no owners were in sight, so she feared the worst - she was an hysterical mess. As we passed a point, probably about 50 yards in front of her a couple climbed over a stile, from a public footpath, to join their dog on the towpath. I'd love to have heard the conversation that ensued but unfortunately we were out of earshot by then (but we could hear she was still shouting).
I used to walk dogs to earn pocket money as a kid and can remember the fear when an unleashed dog approached us and refused to go away - I'm a huge dog lover with only a rational healthy fear of what they can do if you happen upon a badly trained one (instilled in me by my parents when I kept approaching strange dogs with no fear at all!)
Sorry, just one last thing that happened recently. We went on an escorted walk across Morcambe Bay a week or so ago. There were a few dogs present, but two stood out as they were quite large dogs. During the initial part of the walk they were both off the lead and had a lot of fun playing "top dog" with each other - play fighting, running at each other, all very good natured. Towards the end of the walk one of the dogs was put on a lead and the other wasn't. The one off the lead decided to play with the other again to be met with a ferocious response. A puzzled conversation followed - "but they were playing fine earlier". Yeah but the parameters had changed for the dog on the lead hadn't it?
Said me piece now