While booking something else I spoke to CX main reservations/ticketing today (2747 1888) and their take on this is that the charge will NOT apply to any ticket on CX or KA stock. However, the agent I spoke to (who seemed in general to be pretty clued up) said that it will apply to ANY action involving a ticket on another stock, even, for example, making a reservation to take a flight on an open-dated coupon on a OWExplorer ticket on another airline's stock. I suspect things may not actually get that extreme (I can see workarounds) but that is the intent that has been communicated to CX frontline staff.