Late to the party on this one, but my humble opinion is that these zones are set up so that when someone gets in trouble for being out there the park can say, well, you were in a closed zone so it isn't our fault. In other words, to protect against lawsuits.
My dad and I really like watching Jerry's videos. He has really great editing skills and there is a lot of banter that goes on between either him and his friends or him and his wife (that is where the entertainment value skyrockets). She just doesn't put up with his nonsense.
Jerry and @Jammer...