whatever the legality of the order, massa has to take a lot of the blame for getting ferrari in this mess, given he'd already been having trouble on the harder compound judging his braking points, all he needed to do was to make a show of being a little bit ragged after being told alonso was faster before appearing to brake too late at the hairpin, couple of momentary wheel locks to suggest he was struggling and then running onto the nice wide tarmac run off area and loosing the place to alonso.
everyone would have said he'd tried to speed up after getting that message and no one would have pointed the finger. in making it obvious he was gifting alonso the place, massa was making a point that he could have won to satisfy his own ends, though it has resulted in a certain loss of respect back in brasil, if he'd have appeared to have fought and lost, he would have been judged as being poorer than alonso but also as someone who tried to keep alonso behind.
having said that, ferrari could have avoided this just by deciding what to do before the race, when alonso dropped back the BBC suggested it was to save fuel so it would have been far easier / believable for ferrari to instruct massa to switch to a fuel saving program and then alonso powering past , in fact the fuel program wouldn't even have had to exist, to use mclaren's radio as an example if "lewis go to G8 " had actually meant" lewis slow down let jenson past" no one would have known and would have just assumed button had managed his fuel better