Bluesfirewhenkennyburns
He said it would be a light system so if your an adult and you go in with a kids ticket the coloured light indicating a child will flash and the operator will see that your an adult and stop you getting in
I don't really see how that's any different from what we have now.
Even now you have to hand your ticket/st over to a turnstile operator to scan.
Who can clearly see if your ticket/St is a child's or adults ticket.
As others have said its pretty much just left up to the operator to decide whether or not they want to go through the hassle of challenging people, and I imagine it still will be even with the new system.