About the flaps down thing, it means Hijacking, but only if the A/C instead of clearing the RWY at first available interection taxies down to the end and stops.
It must be writen in some ICAO Anexxes (not sure if it's the security or airlaw)
I am quite sure about what I stated because I am quite sure I read it while I was studying for my.
I am mistaken I am terribly sorry!!
Good flying to all of you