Far, actually very far be it from me to defend CO, but the history of the three day rule is the following.

Apparently some number of elites booked on upgradeable fares would reserve a decent portion of BF tickets under someone else's name, then the other person would not show up and just get a refund.

Because there were so many last minute cancellations, upgrades went through. Elites were using this system to increase the odds of a last minute upgrade.

So what did CO do? Look for the abusers? Trace back the cancelled tickets? Trace back the frequent upgraders? No, put in the three day rule effectively negating any last minute cancellations from making upgrades available.

This stupidity (leaving 9 BF seats empty while a 2 million mile platinum stews in coach) is one of the loudest complaints I've heard from loyal platinum elites.

CO would do away with the whole problem if they allowed some number of confirmed systemwide upgrades.