Life is about taking risks. If you never take any risks, you'll never leave the house. Every time you leave the house, jump in your car or just walk down the street, you're taking a risk. My job as a dog trainer is to inform my clients about the risks of certain activities and let them make their own decisions on what they want to do. I can give recommendations and I can tell you what I do with my own dogs, but how you choose to live is ultimately up to you and you and your pack will have to live with the consequences. One way people love to exercise their dogs is taking them to the dog park. There they get to run and play and socialize with other dogs while you get to relax or interact with other dog lovers.
So what are the risks? Well, you never know who is coming into the dog park. I have met people who told me that the dog they brought to the park just jumped into their car down the street and they have no idea who the dog is. So now we're dealing with unknown everything about the dog. He could have rabies or another contagious condition. He could be dog-aggressive or human-aggressive. Unfortunately even owners who have had their dogs for years still bring diseased and aggressive dogs to the park. Who's there to screen them? Nobody. Maybe they get banned but that's only after an incident. Do you want your dog to be the one that gets hurt? The risk is up to you.
The facility alone can be a hazard. No matter how new and state-of-the-art the dog park, dogs still get loose. Dogs dig holes and chew on fences all day every day and eventually they find a way out. People feed their dogs any old thing and leave it around the park for any dog to eat. So if you choose to take the risk of going to dog parks, keep in mind the hazards and always keep your dog up to date on his rabies.
Make sure he is not aggressive and as calm as possible when entering the off-leash area.