Well if not we will be outnumbered 2to1because if it not City fans getting them the Arsenal fans will snap them up
Not sure that Arsenal will snap up all of them, but they should be easily in the majority. There will be so many more reasonably well off Arsenal fans living in or near London who will be prepared to pay for the premium seats, and they dont have the travel costs or the hassle of long train or car journeys to put up with.
If we reach the final then many more City fans will pay for premium seats because they otherwise might not be able to get a ticket. But with tickets for the semi final being so easily obtained then there's no real need to fork out for premium tickets, unless you really want the prawn sandwich experience.