I don't have a pet, only had one in my life, but I am the person who says something to other riders, especially if a child is involved.
I once yelled at my neighbor from my old neighborhood, when we came upon him while riding home, about half a mile to go. He was riding the wrong way on a semi rural road that gets a good amount of traffic, with no helmet. He had his 2 sons behind him. They had helmets on, but I told him to get on the other side of the street. DH was pissed, but I I really think that some people just don't know what the law is.
Of course, this is the guy who got arrested for a DUI in just about the same spot... ah, the local HS football hero from 1981. He got a scholarship to Yale, and apparently didn't learn much.