Our small local park has a top area with a playground that displays "No Dogs" signs. There is a grassy area for ball games, picnics etc where dogs are not allowed, although they can be walked through the path next to it on a lead to the large dog-friendly bit of the park.
I constantly see people letting their dogs run round there.
Every now and again I politely point out the sign and about 50% of the time they will push back with "oh, I didn't think it mattered" "No kids here at the moment are there?" "He/she is no trouble" "it's not for people like me who pick up after their dogs" or something much ruder. Sometimes I will be interrogated about why I care, as if the Council sign is irrelevant.
AIBU to wonder what goes on in these people's minds? These are middle class people with labradors etc, not louts with devil dogs on strings.
(And for what it's worth, I care because grass is not wiped clean of poo when it's picked up, dog pee burns the grass and my son is scared of dogs).