Regardless of the underlying reasons (and I'm sure they're there),
IMHO if the strike goes ahead, it will cost the union and the cabin
staff any and all public goodwill and support they might otherwise
have accrued.

And it's not just going to alienate "a million travellers", it's more likely
going to alienate a million families, plus the millions of others who are
not travelling, but who are thinking "Poor beggars! I'm not travelling
with BA this Christmas, but I certainly won't take the same risk in
future..."
.