Coming late to the conversation (as always) and want to add my two cents (as always).
We do not have a fenced in yard. We live about 1/4 mile from the road and our dogs get free reign outside when we are doing chores (both morning and night), the little dogs as well as the younger dane. The older dane HATES being outside, goes out on a light tie when she needs to do her business and occasionally to sit outside in a patch of warm sunshine for ten or fifteen minutes before coming back in and curling up on my bed.
We do not leave our dogs outside unsupervised while we are gone mainly because of the road. If the pups hear kids next door playing, they head in that direction (but call back REAL quick) - if they heard kids across the road you bet they'd go - the biggest problem is that we live on the road to one of the largest ski resorts in our province, the roads are horrid, there are loads of blind hills and the drivers' are idiots. If we had a fenced yard, I would probably consider leaving my dogs outside in the summer while I am gone to work - only because the younger dane would never allow anyone to come and TAKE anything (as she proved a couple of weeks ago!), but for now all I could do while I was at work if they were outside would be worry about where they're going and what they're doing.
Our "across the road neighbor" had a pup they used to leave outside all the time, considerably closer to the road than we were and one day when I got off the bus afterschool in middle school, it tried to follow me across the road and was struck dead by a skiier coming by. The guy pulled over, and watched while the pup twitched and bled out on the road, and then got back in his truck and drove away to leave 13 year old me with the mess to clean up, the people to tell, and the guilt to live with.
I would never want to put that on someone else. As a general rule though, MY dogs love to be outside, SUPERVISED.
I don't worry *much* about theft ON our property, though over the summer, a girl who was here to look at horses jokingly called Morrie into her car and went to the end of the driveway with him and he didn't worry a bit. The worst part about those outgoing dogs is that they just want to be with people, whoever they are!