I think you have to take into account the course at Dana Point. The last corner (turn 6) is actually pretty narrow and leads into a VERY short finishing straight (+/- 150 meters). They only use half of Del Prado so you only have the right side of the street to make a right turn (effectively maybe 10 meters of road going in to the turn) so there is lots of hard braking as well.
Lining it out from turn 5 isn't in everyone's best interest as you don't have enough time from the corner to the line to move up if you've got it floored (you aren't going to pick up 2 or 3 bike lengths is you're already at 60 kph).
Even though the race is only 3 years old, a pattern is already emerging wherein you'll see alot of monkey business and blocking prior to and coming through that final turn. I think there is a level of panic that sets in when teams don't have their fast guys positioned far enough up on that last lap.
I think slowoldman will remember three years ago when Thurlow actually sat up going into that last corner to spring DeMarchi (?) free.