This bothers me, mainly because, and it does depend on which Motorway, these roads are so heavily used as it is. And it also depends on the instructor. I hope to God, learner drivers are taught about LANE DISCIPLINE!!! It's dreadful in the UK - all too often drivers hog the lane they are in, often the outside lane, and don't MOVE OVER.
I'm all for newly qualified drivers having the chance to drive on Motorways however, but again, have some reservations. I think this should happen AFTER the new driver has passed the full test, and under the restriction of a 'new driver' with an experienced passenger.