I don't really have a problem with this; better the dog was tied up in the shade than left in a hot car. Perhaps it made it more difficult for people to get inside the play centre if they wanted to avoid the dog, but there was another way for people to enter. Was there another shady place the dog could have been tied up that wouldn't have inconvenienced anyone? As long as the dog was settled, not barking or jumping on people, I think it's ok. Maybe the owner had tradespeople at home and couldn't leave the dog there but needed to take the kids out and entertain them? Or perhaps the dog just likes an outing!