If you happen to be one of those foreign pilots you have two choices I guess: go sick or be a
This sort of nonsense comes up time and again. Under UK law (and I'd have thought most of those operating out of AMS on the day in question would be UK based) refusing to operate in these circumstances could (would) be considered secondary industrial action. If the union encouraged a sick-out, they would face legal action. Individual pilots would be open to charges of gross misconduct and summary dismissal.
It's very easy to throw around terms like
, but it's in no way helpful to the debate, and completely ignores industrial relations realities under UK law.