Richard wrote:

On Fri, 01 Nov 2013 00:32:06 +0000, Cliff Frisby
wrote:

I don't know whether I am mis-remembering something, but I thought it was
obligatory for a bus operator to issue paper proof that you have paid for
the journey you are making, assuming you don't already have it. The
purpose, I always assumed, was that it protected the innocent passenger
against false accusations of fare-dodging.
[...]
A piece of plastic with the information buried in an embedded chip and/or
a remote computer under the sole control of the operator doesn't provide
any sort of objective evidence, as far as I can see.

I would argue that the proof of payment is still there, it's just in
the card and can be read with appropriate equipment.

Well, I think that really misses the point. Proof of payment does not exist
if the ability to reveal it depends on the integrity of the party demanding
the proof.

It's as though I bought something in a shop and, when asking for my receipt
to ensure there are no problem passing the security guard on the exit, am
told I don't need one because the shop has all the evidence it needs to
satisfy itself that I paid for the goods.

There's also a parallel with the move from signing credit card
authorisations to chip-and-pin.

We are being coerced into having to trust potential adversaries.