From my experience with dogs who aren't on a lead, they don't know boundaries unless their "masters" are with them and they are somewhat trained. If they go on one neighbors property roaming, they can go on anyones property given enough time.
Don't get me wrong, you'll always have that exceptional dog who never leaves sight of their "home", but even then, "nature" can kick in and off they go be it a running rabbit or other 4 legged creature, or they aren't spayed or nurtured.
I just live in a rual county where for whatever reason, people who own dogs don't either fence them in or watch them, and they're roaming all over the place.
I have a blue tick hound that when we first came to us you had to watch him like a hawk or off driving around roads I went looking for him. He use to drive us up the wall because he'd be good at being outside, then, you take your eyes off of him for 5 minutes and I'd bet getting a call from my neighbor telling me she had seem him running across the field in her backyard across the street. He would always be wearing the training collar LOL This guy is now one of the older ones in our home, and his running days are expired, and we never have to worry about him wondering around because he finally realizes how good he has it LOL
I only have barb wire going around the property lines, but a Dogtra training collar/collars has worked wonders when we take anyone out back for a walk with us.