Yeah, but I think that the main message is that there are pilots in the cockpit who can easily override any weird input. Even if it is theoretically possible (hey, you never know, right?) to impersonate avionics and mess up with the FMS/ECU/EICAS, there's no such thing as a pilot going "holy crap! the plane is going sideways and there's nothing I can do!". I'm pretty comfortable calling this whole "hacking the engines from the in-flight entertainment system" fiction.