Originally Posted by continentalclub

Quite simply, if more than 5% of return WT seat bookings are already being upgraded for operational, commercial or other reasons, then there may be no benefit whatever in booking through STA.

My point is that it is not possible to prove, even within their Ts & Cs as presented, that 10% of bookings will benefit from a sector upgrade, nor absolutely guarantee that they could. There are a finite number of seats.