This is one area where the RFU are way behind the rest of the sporting industry.
Access control is standard across the Football Premier League and the vast majority of Championship clubs. Horseracing uses it, cricket uses it, silverstone has it as well.
It's expensive to install, but the savings can be huge on combatting fraud. I installed the first ever Access Control system in the Premier League.
Season ticket holders have an RFID card (like a credit card) and casual visitors have a barcoded ticket, although you can also get RFID paper tickets (Man City use these).
The problem with the system the RFU has now is that they can't reprint or reissue tickets, because there is no way of stopping the old one from being used, and thus having more than one person in the ground for the same seat.
With access control if a ticket is reported stolen or lost, you reissue it, which automatically cancells the old ticket. Turnstiles use a simpole traffic light system to indicate whether a ticket is valid or not and stewards with handheld PDA devices can interrogate tickets or cards to resolve issues. The turnstile lights also indicate if the ticket is an adult or concession, so its very easy to scan the lights and catch adults coming in on junior tickets.
You save a huge amount on fraud and it also allows you to cut down on turnstile staff since one person can manage 4 or 5 turnsiles.
It also allows the use of print at home tickets, and gives you stats on who came in, when and where. This can be linked to things like facebook, so that your status on facebeook is updated when you buy a ticket, and again when you enter the stadium. Our concourse catering tills can also be used with the system, giving discounts based on when you enter the ground (to encourage people to enter earlier). An SMS system can be used to tell people about these offers in real time.
Using this system we have discovered that around 1,000 season ticket holders fail to turn up every game, we can then market them, or encourage them to use a ticket exchange program to help us fill the stadium.
Its totally unbelievable that a stadium like Twickenham doesn't have access control in place.
There was an incident a few years ago when the Millennium Stadium in Wales was being used for the FA Cup where a whole bunch of around 300 or 400 tickets went missing in the post. Because they didn't have access control then, all they could do was leave all those seats empty and not allow anyone to use them. With access control they could have reissued all the tickets meaning the old ones were useless to whoever stole them. As it was 300 to 400 fans never got to see the game because they never received their tickets.