Suppose you arrive at a tube station and touch in, then quickly realise you won't be able to make the journey you hoped to, perhaps you've just missed the last train, or the line you wanted to catch is closed for engineering works. You'll need to ask a member of staff to sort out the touch-in. It seems sensible to me to allow the passenger to be able to do this themself. You could add a couple of restrictions, say only allow the option at the same station, and only within 15 minutes, to prevent any abuse over a short journey.
One example I can think of personally was at Highbury & Islington recently, I arrived late at night, most of the staff had gone home so the barriers were locked open, I touched in through the barrier, then realised I'd just missed the last Victoria line train. The info/tickets desk was closed, luckily a member of staff who was on his way out offered to help and sorted the problem for me and my friend. He accessed the machine with his staff card and entered a PIN number I think, then removed the touch-in. It was nice of him to do so when he'd clearly just finished his shift late at night, some people wouldn't have bothered.
Anyway, is there a good reason I can't think of why the passenger couldn't just be allowed to do this themself? A simple warning such as "your oyster card is no longer validated for immediate travel" would suffice.
One example I can think of personally was at Highbury & Islington recently, I arrived late at night, most of the staff had gone home so the barriers were locked open, I touched in through the barrier, then realised I'd just missed the last Victoria line train. The info/tickets desk was closed, luckily a member of staff who was on his way out offered to help and sorted the problem for me and my friend. He accessed the machine with his staff card and entered a PIN number I think, then removed the touch-in. It was nice of him to do so when he'd clearly just finished his shift late at night, some people wouldn't have bothered.
Anyway, is there a good reason I can't think of why the passenger couldn't just be allowed to do this themself? A simple warning such as "your oyster card is no longer validated for immediate travel" would suffice.