Just to clarify - I would absolutely have intervened had I ever seen any animal with the kind of coat in the photos. That was a case of extreme neglect. I was wondering more about the kind of "daily neglect" like my neighbours cat. Nothing extreme or cruel, just slightly worrying. And I'm not worried about any legal repercussions, more about how do you broach the subject with otherwise friendly and normal people. Cats with long hair do tend to get matted, but most people tend to it regularly.