Riders have every right to leave the track on a warm up lap.
The ones that left should just have been made to start from the pit lane like the rules state.
The riders/teams ***** up pure and simple, they had a free choice of tyres exactly the same as Miller had, they chose wrong, pure and simple.
Make them all start the race on the ones they freely chose, then come in after lap one or two.
Or like the rules clearly allow, you can leave the race track on the warm up lap change bike, but then start from end of the pit lane after everyone else has passed the exit of the pit lane.
If more than one starts like that you have to leave the pit lane in single file, and cannot overtake until you have passed the end of the white line delimiting the end of the pit exit lane onto the race track, there is zero safety concerns over that.
The rules are very clear, and completely cover the situation that arose.
They just made up new rules on the spot, because otherwise Millar would have had such a huge lead he would almost never have been caught, and obviously the "golden boy" cannot be touched or given such an obvious disadvantage.
But any start that gave Millar such a huge advantage as that would have been just and correct as he was the brave one making the hard call, and ultimately got zero benefit from it
Then MM .........WTF
He should have been black flagged for turning around on the gird, not a ride through.
Once he knocked Rossi off he should have been black flagged there and then, and should probably be banned from next couple of races, as he should never have been on the track in the first place.