Being a B1 with avionics extention, therfore not knowing much about the black arts, should some unsavoury character get themselves in a postion such that we'd accept software from them, what's the worst that could happen to modern aircraft such as the E170/190, 737NG, a320, etc? I did the Embraer B1 B2 course and seem to recall that a lot of software can be changed on that aircraft.