Has alex ferguson sent out a message saying only tarts not prefects can expect to last the full 90 mins......?

no. Fergie said he took of Rooney because he didn't think Rooney deserved the booking. The ref reacted to the crowd, and if he gave rooney one fake yellow, there's no way you can be sure he wouldn't give a second. Fergie pulled out Rooney because of the ref, and he said as much