Originally Posted by
SAT Lawyer
The good thing about a Y-up is that it is a fully refundable fare. If you buy the Y fare and then find the space lacking for the immediate upgrade, refund it and pick another flight with existing upgrade space or purchase a less expensive fare and take your chances with the complimentary elite upgrade process.
Not all Y fares are refundable. I haven't seen many non refundable ones, but they may exsist. Also, some Y fares may also be advance fares as well, such as a 7 day advance purchase fare.