After reading all the posts on ZED, I would like to add that if you travel within Asia, airlines will only accept a ZED if it shows the origin and destination which must match the route of the flight you hope to board.

They can but will not re-issue a ZED ticket.
ZED agreements clearly state that an airline that has a ZED agreement with the issuing airline can re-issue a ticket if there is a change in the required routing and can collect any extra costs.

I recently wanted to travel BKK - BNE on TG (non stop flt). I held a BKK - SIN (TG shown as carrier) ticket and a SIN - BNE ticket both ZM fares. The TG staff would NOT accept both coupons and put me on their non stop flight which was wide open....totally rediculous...but believe the TG staff are just not taught or empowered to make decisions like this (even supervisors). This mentality is prevalent within asia..

So make sure you hold ZED tickets in all combinations if your routing might change due loads etc.