I wouldn't "move out into" the lane when a car approached, I'd already be there. Since overtaking traffic is rare, just how is this unsafe? No other vehicles are even coming! When one does come along the cyclists will see and hear it approaching with plenty of notice to move to the shoulder if they choose. The only time this would be unsafe is if the motorist continued his course and speed with the cyclist plainly in his view, AND the cyclist stayed in the lane while watching this unfold. Two very unlikely conditions in my experience.