I've noticed that whenever I visit a park with other sims who visit with their pets, the other sims for the most part ignore their pets. The following pictures represent perfectly the activity that occurs at the parks I visit.
Dog owners who visit parks with their pets don't interact with their pets at all, they don't pet them, socialise with them, use the obstacle course equipment or pet toys if they're available, don't play fetch, don't train them, the most that happens every so often is a simple interaction that I'm pretty sure the dog initiates, but what you see in the picture is normally what happens, everyone is either playing chess, or watching other sims play chess.
This isn't just a problem with the pets, even if there were no pets around this is pretty much what happens at the park. Why don't sims walk around the park, or do some activties that are available at the park, or socialise with each other? They seem so magnitised to chess. Can this please be changed? Perhaps this is a bug of some sorts? Either way it's such a shame that a whole environment dynamic is being wasted because everyone wants to play chess.