My dogs have a large fenced back yard but they don't get too much time out there.... heck, in a winter like this one, they've barely got trails out there and a crust layer 8"+ down is dinging up their feet anyway.
Basically they get all the exercise they need in harness. I'd like to have more time to free run them in the off season, but even in very rural areas there are sufficient dangers that the e-collar and a vigelent eye is a requirement as far as I'm concerned. Should I tell you about the time Anya hit a barbed wire fence dead-on while clipping along? Or the log trucks that have come around a corner with dogs scattered in front of them? Or the time a kid suddenly appeared coasting a disabled motorcycle off a ridge at high speed? *sigh* Oh, and no tangles with cougar. Yet.
If getting the itch off your hound is an issue in suburban areas, I HIGHLY recommend scootering. You're not breaking any laws, your dog is quite safe, and s/he will get better exercise than if it was just start/stop free running anyway.