The area above Disneyland IS a
no-fly-zone although there seems to be a bit of contention as to the need and reason behind that.
As for the flights, of course the "no-fly" edict is for commercial aircraft and not military fly-boys. In this case I would have to guess "joy ride". If you were a cocky fighter pilot (that's a given for fighter pilots) on a flight path that took you near Disneyland wouldn't you be tempted to buzz the place for a good look? Try to get the tail number it it happens again
It's possible it was an "interdiction" of a civilian aircraft that got too close but I REALLY doubt the area is that closely monitored. I base that opinion on the fact that here in DC we have had a
many cases of planes flying OVER/near the Whitehouse before and after 9-11. In each case they were intercepted only after the event in most cases by a polite radio message to land at a specific airport and come talk to the nice gentlemen in suites.