This promotion only requires that you book after registering, and can book any time this year. Someone was a bit overeager in merging this thread into an old one about a different promotion and now we have a mess with a giant thread talking about two different sets of terms and conditions for two different promotions, which are just similar enough to confuse anyone trying to read it.

To reiterate, you can register now, and book and fly by Dec 31, 2014 to earn double MQM&RDM on all flights from Seattle to select destinations as long as you originate or end your trip at SEA.