Old fart golfer chiming in. I've played many golf courses infested with Canadian geese. I was attacked once a few years ago. My guess is the goose had eyesight problems and thought I was a threat. The goose took off once it hit my golf bag. That said, domesticated geese and swans are equal to guard dogs.
I’ve been attacked by geese and seen people attacked by swans. I have read that black swans are even more aggressive!.............