Originally Posted by
javabytes
I think this is only partially correct. While the MQM/mileage bonus is certainly gone, I don't think the upgrade list is protected so much, especially in IROPS situations. Travel disruptions probably still affect the upgrade lists, especially so when you are lucky enough that your new fare class becomes F/J and allows you to rebook front cabin seats on a positive space basis, jumping the upgrade list altogether. While you don't get the mileage bonus, it does open up your options greatly.
Correct, except that deep in the system there are apparently mechanisms in place that will prevent you from even getting onto the upgrade list in certain situations, based on your original fare class.
I do agree that rebookings into F/J will bump others out of upgrades, but generally, I've found that this is only done when warranted (in case of VDB or if already booked into F using miles/SWU (but not comp. upgrades)).