On Tue, 5 Mar 2013 09:42:04 +0000, Roland Perry
wrote:

In message , at 22:38:02 on
Mon, 4 Mar 2013, Richard remarked:

Well, it's not really a fine. It's a charge for not being able to
demonstrate that you've done the right thing

The Paywave terminals[1] don't give receipts, so it's quite difficult to
demonstrate [2] that you've used the card.

Yes, to be clearer I meant demonstrate *somehow*, but I agree that
there is a difference that I hadn't thought about: the Oyster knows it
has been validated, the bank card doesn't, but I don't think it really
matters -- if you have seen the green light and read the message, the
chances of you later being found not to have paid are almost zero.
False positives are going to be in the user's head, did it register my
card? I think this sort of problem is easier to imagine at a station
gateline than on a bus.

Richard.