Earlier quoted context omitted.
I frequently walk my dogs without leash. They follow my command, don't disturb other people or dogs unless both parties engage and generally I don't do anything that someone who has a leash wouldn't be doing. They also walk side-by-side with me when off-leash. This is very common in the city I live and surrounding area (Barcelona, Spain and Catalunya). Both me and others without leashes are indistinctive from people…
The problem is I don't know your dogs are well controlled. I've been bitten twice over the last year by leashless dogs. This could of course be solved by introducing stiff penalties for owners of unleashed dogs who bite -- how about a fixed 10,000 dollar fine?
If such a law were ever to be passed, something tells me a lot of people with "well behaved" dogs would suddenly start to leash their dogs "just in case".
Humans are very predictable in that fashion.