Originally Posted by
Viajero
I don't see the point of the question; no current aircraft is capable of doing NRT-GRU, or LHR-SYD, so what difference does it make whether they would refund anything or not? Besides, the rules applicable to a ticket are those current at the time of first issue; if things change later, for better or worse, you are stuck with those rules and no refund, or increase, is due anyway.
Technically that isn't exactly true. If you have issued the ticket and flown a segment in it, then yes, when they reissue, you will be stuck with the rules applicable when the ticket was issued. However, if you have not flown the first segment yet and ask for it to be reissued, they will have to recalculate your fare and use the rules based on time of reissue. eg. refund then issue a new ticket.