This stirs up some uncomfortable memories. About a year after I was married my parents moved away and took my childhood dog with them (I was going into an apartment and couldn't take him). My dad was out walking him as he did every day. An unleashed (much larger) dog came up to him and attacked him. It was a serious attack and my dad was so shaken up. My mom said he was shaky and pale when he got home. After a vet visit which required stitches and antibiotics my dog was OK. I don't think any dogs should be off leash anywhere. Just my humble opinion.