I'm not buying any, don't worry.
But there's several countries involved in building them and they also have schematics. You'd think at least one would have raised alarms by now if there was truly a kill switch.
The real real kill switch is ALIS access and parts availability. Those two things can ground the planes until a replacement system is developed and parts manufactured.
I mean it's probably not going to be much shadier than the OS itself. Fuck Windows.