ok- thank you!
this just reinforces my decision to keep him on a leash at all times, unless in fenced area (as he does once a day at park ).
but for casual home walks with neighbors dogs he will stay leashed- as he is a very curious 2yr old B, and loves to run! and has tons of energy..
now i wont feel guilty when i see our neighbors dogs off a leash and he is on one.