TC wrote in message

Personally I fail to see why we cannot just walk up to a ticket machine
to customize the properties of the card - so that the first time each
day we use the ticket, the amount for our chosen travelcard is taken off
and the ticket converted there and then for the rest of the day.

Then why not just buy a ticket? The advantage of oyster is supposed
to be that you don't have to go to ticket machines or ticket offices
every day.

Capping is probably going to be full of bugs when it first rolls out,
and is bound to have quirks for years on end. Personally I'd like to be
able to specify the ticket before I travel, without having to worry if
it is going to overcharge me - but still have the convenience of not
having to rip the oyster out of the wallet, or standing in an endless
queue at the station.

Rather like congestion charging Oyster is a brave attempt (don't get
me wrong - I'm using it and wish it success) to introduce an IT based
charging system at a time when the 'people tracking' technology isn't
quite good enough to deliver the sophistication ideally needed.

In time there is no reason in principle why the two systems could not
be merged although, not being an IT person, I would not seek to guess
the complexity. However, use might be made of a GPS based detection
system, as proposed for the national congestion-charging proposals.
If this system is going to be fitted to all road vehicles then why not
the railways too? A real personal 'Travel Card' could then detect
whether you're travelling on a train, bus, tube or car and then bill
the appropriate fare (including price caps) or congestion charge to
your bank account. Post-pay not pre-pay, a credit account just like
gas/phone etc debited once a month or whatever the customer prefers.

Civil liberties need not be an issue - unregistered pre-pay cards
could still be available to those who wish to travel incognito, might
just cost a bit more. Or, if you're a bona-fide criminal, you could
just steal one.