I thought of doing this myself but I'm affraid it's going to be too much of an hassle to color the hair close enough to the base and keep the blond color from reappearing (which is something a wearer with very dark hair like mine doesn't want to happen).
I must admit it though it would be the best solution, not only to eliminate the knots, but also the orange tint that usually shows under a strong light source, including the sun.
Regards