When the type of operation requires a CPL in order to be conducted!!
If it only requires a PPL then you have no choice but to work for free, oops I mean Volunter!!
I have no problem with people gaining experience in club aircraft, ie: glider towing, parachute jumping. But if the operator is selling services to the general public (ie: tandem jumps to non club members) then surely the pilot should be getting paid and hold a CPL?
