"I wouldn't just generalise "just Europeans" there 411A. I wonder how many pilot types (especially the weekend warriors) that are aware of this in North America.
Or indeed that there is anywhere outside North America?
Yes, in a real war I would indeed expect all radio navigation aids to be turned off. But since both civil airlines and private flying would also be likely to be banned, would it really affect anyone?
Y-code GPS would probably continue - but CA-mode would be off for the duration.....even with SA re-enabled.