"Takes about 20 seconds to reprogram an IFF."
I agree.But what do you program it to? Unless you have the codes? What do you program it to?
Any aircraft which is not IFF confirmed is red. And red is not good. It is bad. And it will not last long no matter who is piloting the aircraft.
Well, that is unless your are flying over insane Liberal-land, where they are required to respect "diversity" of IFF. And, of course, you never fire unless you are fired upon, even if that fire is a nuke down your throat. Of course at that point, you cannot 'fire back'. But that does no matter to the PC American government.
It doesen't matter to them. They are fine and dandy with it.