Thank you Mary Katherine for that very clear response, which is what I was assuming it must be. I do think it's a slippery slope to apply labour protection practices to artistic endeavour - but my own union has not always been white as the driven snow on that issue!

I suppose if the rule started out with orchestras and show bands etc. in mind it does make a bit more sense, but I'd argue that every UK-based folkie (even one who'd started out in the States), in fact all folkies everywhere, are unique - because that's the whole point of what we do!

Presumably, your authorities - like ours over here - are not too familiar with the genre. Shame.