westie...........obviously (from your post) it is acceptable for pax to buy a row of seats to accomodate a broken leg - this then is what the boy should have been made to do by the airline!! I have no idea how someone could be 'strapped in upright' - the mind boggles
but 'unsecured' cabins happen all the time (in my part of the world) and one just has to hope that nothing goes wrong!! (and no it doesn't make it right) just a fact of life.
Perhaps the airline thought they were doing him a favour by not making him purchase extra seats (and they did give him an empty one next to him).............probably a favour not likely to be repeated!!