Quote: Jeff the God of Biscuits "Ticket prices as noted above, but, they will NOT be selling concession tickets on the day at Salford, just full price tickets. SO if you want a Junior/Student/OAP/Disabled ticket you have to book in advance.'"
I think the message was (or at least should've been) that you can only pay £18 at the cash turnstiles on the day.
Juniors/Students/OAPs/Disabled CAN pay on the day, but will have to queue at the ticket office to buy a ticket, which can then be taken to a ticket turnstile. As this takes a while (and Juniors/OAPs/Disabled may well not be up to the wait especially if it rains, as the queues for tickets are not covered) it is strongly advised that those want a Junior/Student/OAP/Disabled ticket book in advance.
Hope that clarifies things, see you on Sunday!