Isnt it obviouse why the Scots are all willing to fight to the death to avoid English rule. Its through inspriational speeches like:"THE FREEEEDOOOM... to be ruled and taxed by this set of Norman decended French speaking aristocrats instead of that set of Norman decended French speaking aristocrats."
Or maybe the local leaders will just side with whichever faction looks like its going to win in the end who knows. Although I suppose some medieval people did take quite strong views on which family tree had right to what land.