I have lived with/owned dogs all my life, and trained and handled them for show too.
It bothers me that dog owners nowadays seem very rarely to carry an emergency muzzle.
I have never had a dog I have been frightened to handle no matter the situation, and I have never been bitten. However I have had dogs that were injured, in pain or extremely distressed, and all dog owners need to know how to prevent a dog from reflexively biting in that situation. A dog that is injured needs to be handled safely for your sake and the dog’s too. You can’t help them if you are at high risk of being bitten, and they can’t help their base instincts when they are in pain and don’t understand why you are trying to haul them around.
I always have one in the car and one in my pocket by the poo bags. I never expect to have to use it on my big lassie for aggression, but if some reason I did need to demonstrate that she would not bite, I could. I can make her visibly safe to be around even nervous people. It doesn’t hurt her or bother her, and if I ever need to use it on her it will not be a new experience.
Dogs unmuzzled and off lead in a busy park is an invitation for trouble. It will probably not be the poor dog’s fault, but by god the dog will suffer the consequences. It’s essential to be a considerate and civilly-minded owner.