"Because they can't totally lock it down, so they should assume sometimes (and this is extremely rare) people will wander in"
According to the article there is a one hundred million dollar security system in place that is supposed to prevent people from just wandering in. That system failed in a public and embarassing way.
It's interesting that they bothered to put up an 8ft fence but not line it with razor wire. Barring wire cutters, I doubt this guy would have gotten over.
Well, you're right, razor wire would cost a few tens of thousands for the 10 miles or so, and would be effective in stopping the casual intruder, meaning more attention could be focused on those that do get in.
The hundred million dollar electronic security system is likely part of this - obviously there is no need for razor wire (or guns held by pilots in cockpits, something many pilots want) since the electronic system from the defense contractor that costs tens or hundreds of millions will save the day.
According to the article there is a one hundred million dollar security system in place that is supposed to prevent people from just wandering in. That system failed in a public and embarassing way.