I am looking to purchase a ticket with the intent to UG using PP. The flight I am looking at is in Q class. What's interesting (and confusing) is that Basic Eco, Eco, and Eco (refundable) are all the same class (Q). I figured Basic Eco would have its own fare class. Q class, even as a basic economy ticket, appears to be eligible for UG using PP. Is that true? The following is really an academic exercise, but if I know that the flight I am taking historically has ample UG space such that the PP will clear, is there a reason I would not want to save $90 per ticket (other than PQP, lifetime accruals, security, etc.)?