Ignore this bit - I was confusing myself on the relative minor

>>But (in the unlikely event one wanted to) not the additional relative minor as the second (not 5th) might be used? So in your example F#m on a D whistle is taking the p**s because the G# (not C#) would more likely turn up in the tune or song? :)

And you couldn't play a G and get away with it so it would have to be half holed to stop it jarring