Alex: This issue raises it's head time and again due to the rather "quirky" FAA legal interpretation. However, it simply boils down to who is considered the legally responsible person charged for the flight. This can only be one person - if you doubt this imagine, for me, what would happen on a IR training flight if the flight caused an airspace violation or worse. Who do you think the "Feds" would come after to take to court or fine?