Originally Posted by
climbermom
Y-up is not guaranteed. Two weeks ago, I booked my husband, myself and my son on Y-up fares from PHX-EWR. Except when it came time to complete the purchase, only two F seats were available (and no other fare class was available on the sold-out flight).
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.