Paying For Chance Of System Wide Upgrade (SWU)?
Last year on Continental I could use systemwide upgrades without restriction (space available).
This year I tried to use one to fly between Hong Kong and Chicago on United, and found I must pay approximately twice the lowest economy fare available from CO for my ticket to be in the right class to be eligible for an upgrade to business. This was not the case last year on CO.
I paid an extra $900 to be eligible for the upgrade, and now I am waitlisted, and have been for a couple of weeks). There is no guarantee that I will be upgraded so, if I am not, I have paid an extra $900 for the chance of being upgraded.
My suggestion is that others who find themselves in a similar position, call Continental/United and ask if the extra money they paid on booking will be refunded if the upgrade does not go through.
CONCLUSION: Free SWUs are not free, and attempts to use them could double the price of your economy class ticket.