I am good friends with the pilot that flew WhiteKightTwo on that formation flight.
It was a well planned flight, with FAA blessing. It was arranged for PR when VG opened their terminal at SFO. They parked WK2 and SS2 by the VG gates an there was a big party for VIPs. Virgin is all about big PR events.
If you look close in the video, you will see a Baron behind WK2, it was shooting video from the opposite angle so they had shots with the VG plane in the shot. That is what they really wanted out of this flight. There are also photos of them flying over the Golden Gate.
As far as VG pilots flying for Virgin Galactic, well that was a bunch of PR too.There was an article back in 2008 or 9 that said they would recruit pilots from VX and Virgin Atlantic. They even interviewed the CP and head of training at VX and they said they were going to do it.
In reality, there are currently only 4 pilots at VG.
CP is a former British Test pilot and flew with Red Arrows. Other 3 are, former Shuttle pilot, ex U2 pilot and Air Force test pilot. So unless you got that kind of background, keep dreaming.