Who knows really, but from what I have read from the race reports, Rossi's bike was still running, Casey's had a tilt sensor and stopped. the marshalls were unable to push start Casey's bike anyway from what I understand, so it was probably irrellevent anyway.
But, as I said elsewhere, the whole move from Rossi, just smacks of desperation, not of the unflappable, confident multiple world champion that he is. I think he is struggling so much with the Ducati and knows it.

"I hate to advocate drugs, alcohol, violence or insanity to anyone, but they've always worked for me" Hunter S. Thompson.
There are really only two questions in life. 1.Which way do i go? 2.What is the lap record?