(Go Israel, Go! Slap 'Em, Down Hezbullies.)
They must be waiting for the Lebanese army. Do you suppose it is made up of barbers and hairdressers like the Belgian army is?
I suppose they could patrol it by air. Announce it is a "no man zone" and anything found within the zone is subject to being bombed or shot, then patrol by air.
Also, I would presume they have access to some of the same technology we have, they can seed the area with sensor that would pick up people moving around.
Then if they find anyone in the zone, drop a bomb on them.
Would it be 100%? Who knows, but would you really want to travel across open territory knowing that your movements can be picked up, and a bombed dropped on you the minute you are detected?