Originally Posted by
Xandrios
The reason why they do not let people buy up is to enforce their fare rules. Otherwise you could do the following:
- Book a very cheap flight that does not allow cancellation
- Upgrade to a slightly more expensive fare that does allow cancellation
- Cancel the flight and get a refund while your original ticket did not allow that to happen
Which generally does not work: even if you "upfare", the original cancellation and refund conditions remain applicable. This is specified in the fare conditions.