I've been told by a lad who works on the Man City / Etihad campus that the turnstiles we used at the weekend were only installed this summer, and include facial recognition software.
Whilst it's primarily been put in place to quickly identify those banned from grounds, there is also a suggestion that other PL clubs will follow suit and, in due course, your facial scan at the ground will need to correspond with a photograph held / data received from the issuing club. So basically not dissimilar to these automated passport machines at the airport.
It might take a few years, but I can see it coming and at that point, each PL club will know exactly who is in their ground and if they 'deserve' to be there (on their terms, of course).