Updated response from QF:
Changes to Qantas Ticketed Bookings on Mexicana
Qantas Commercial Policy
31 August 2010
As of Saturday 28 August 2010, Mexicana Airlines has suspended all operations until further notice. No new bookings on Mexicana services can be made while its operations remain suspended.
This situation is beyond Qantas' control and we regret any inconvenience caused. We encourage customers wishing to travel to Mexico to consider services offered by other Qantas partner airlines, such as American Airlines and Alaska Airlines.
The following commercial policy outlines the options available to passengers holding a valid Qantas ticket issued on or before 28 August 2010 who wish to make changes to their bookings.
Passengers may, without fee:
• Re-route travel to/from their original destination using alternate carriers American Airlines (AA) and Alaskan Airlines (AS) only (refer to the booking class table below)
• Bypass original destination as a stopover point and continue to the next ticketed destination via the most direct routing using Qantas, American Airlines (AA) or Alaskan Airlines (AS)
• Retain the value of the ticket in credit for future travel within 12 months of original ticket issue date. If the new fare is more expensive than the existing ticket fare, the fare difference is payable by the passenger. Applicable ticket taxes may apply
Conditions
• The new flight must be for the same cabin of travel (e.g. First, Business or Economy)
• The permitted booking classes for AA and AS are outlined in the booking class table below.
• Refunds will be offered where travel has not commenced and fees waived for tickets issued prior to 28 August 2010
• Any third party costs/penalties, such as hotel or other ground operator fees incurred will not be waived by Qantas
• All other rules and conditions of the ticket remain unchanged
http://www.qantas.com.au/agents/dyn/qf/policies/MexicanaWaiver310810.pdf