Originally Posted by
Sixth Freedom
It is a bit more complicated than that in practice though.
On unconstrained flights there will be no difference because the seats would otherwise be unsold. And on heavily constrained flights there will be no difference either because no seats would ever be released in the lower fare classes. But there will be some flights, most likely during the school holidays, when I class fares would previously have been available but will now not be.
This is true but for constrained flights it is only true when Min(Fare Paid) = Max(Fare Paid). Based on my experience as a revenue manager those flights are extremely rare. Also those flights where it happens, unless it is full Y, it is likely to be bad due to revenue management practices and not optimum within the fare structure they have to work with.