Does anyone have any input as to limitations on sharing the tow cost of a glider flight between club members in a two place glider where one is a student pilot and the other is private glider rated? This is in relation to the FAA rules about what costs can be shared and the portion of the cost allowed for each person in the aircraft. Can the student pilot pay for the full tow fee without it being considered compensation for the private pilot, or improper sharing of the cost?