Without "No dog" Sign does not mean you can not your dog can run freely without chain. Even in European countries e.g. Finland, you can only release the chain of your dog in the dog park. If your un-chained dog attack people, your dog will be shot (in both EU and US) by gov according to the law, and you will be responsible for everything occurred. If you really love your dog. Don't let it run without chain in public areas.