I could understand the three carmakers wanting their own test drivers driving, or even wanting to go to an impartial track (since the P1 was developed in part at Dunsfold), but the ridiculousness that Ferrari is pulling is just absurd and childish, and hopefully they lose customers if they don't come to their senses.
Major kudos to Porsche for agreeing, without caveat, to track test their car, even knowing full well that it's likely going to lose. This makes me more interested in buying a Porsche than the other two (if I could ever even afford one of the other two).