This certainly seems to be enforced for the Thunderbirds and Snowbirds. But, I watched the whole FA-18 demo from the regular burn line on Thursday. The same routine he flew on Friday (when the other burn line was in effect). And the F-16 demo the days before that.
I agree that if something went wrong that the extra space probably wouldn't help a lot. But it's really hard to put the Jeannie back in the bottle. I'm afraid those rules are here to stay.
As far as jet teams go, I don't mind seeing them once in awhile but I don't want to see them every year at Oshkosh! Please give us extended homebuilt and vintage reviews in stead. And yes, less narration please. We all know those stories by heart now. In fact we can correct them when they make mistakes.