Roland Perry wrote:

In message
, at
14:11:42 on Sun, 8 Aug 2010, CJB remarked:
TfL explained that it could not be aware of any over-charging until
the issue was reported by a passenger.

Apart, of course, from looking for cards where there were two top-up
[bank charges] on the same day.

Yes - some passengers will do that, but that doesn't actually matter.
What you are looking for is top-ups where there were two debits but only
one amount of credit added.

Not holding an Oyster card, I wouldn't know, but in many cases the
financial part of e-transactions is handled separately for security
reasons. If that is the case here, then how would TfL know in detail
about the debits?

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