On 02-Mar-12 09:19, Adam H. Kerman wrote:
John Levine wrote:
But to return to the original point of this exercise, to get free
train travel, buy a $20 Visa gift card for cash at the supermarket,
and use it on the train. (Do they even have gift cards in the UK? If
so, make it a 20 quid gift card.)
Until you've bought $20 worth of tickets, it works normally, and the
ticket price is deducted from your balance when the transaction
clears. After that, the bank rejects the transaction, but if the
guard's ticket machine doesn't validate in real time, by the time that
happens you're long gone, and since the card is a bearer instrument,
they have no way to know who to go after. Repeat indefinitely until
the expiration date on the card.
Knowing the BIN ranges of debit cards and gift cards doesn't help
here, since many of them are entirely valid and the train company
will get paid.
Stephen raised the spectre of gift cards to dispute the point I made
that card types were known by number ranges,
I only raised the "spectre" of cards with insufficient funds to accept a
transaction but which were not "closed" or "invalid". Gift cards are
merely a trivial example of that, and banning gift cards (or debit
cards) from trains does not solve the problem, if it were even possible.
so you just need the list
of known closed accounts when using a hand-held point of sale device
carried by the conductor, given that authorization won't be convenient
or possible when using these devices.
There are hundreds, if not thousands, of millions of closed accounts,
and more every second. It is not feasible to store that list in credit
card terminals, and it would be out of date before it even finished
downloading! Given the rate card numbers are invalidated, it's possible
that you could _never_ finish downloading, like the old story about the
Chinese walking single-file into the sea.
Even you agree that yes, these are issued in known number ranges. If
the transaction with a gift card cannot be authorized in certain
circumstances, then don't accept it in those circumstances.
Why restrict that to gift cards, though, rather than _all_ cards?
Similarly, they're not going to accept cards issued by merchants to
give credit to their own customers for purchases at their own store,
like gasoline credit cards. The accounts are issued in different
ranges.
They should be in the 6 range, and the merchant limitation is enforced
by the issuing bank, not the merchants. The merchant just swipes the
card you present and waits a few seconds to see if it worked.
This Web page discusses payment methods that also apply to paying
on train: http://www.nationalrail.co.uk/times_...t_methods.html
Credit/Debit/Charge Cards
All National Rail train companies accept the major cards
such as Visa, Visa Delta, MasterCard, Maestro and Amex.
Some train companies also accept Diners Club International,
Solo and Electron.
Nothing on this page says that gift cards are accepted. Gosh. They
must know the card number ranges!
Why would they care if it's a gift card? A card is a card; as long as
the transaction is authorized, that's all that matters.
So many followups later, Stephen's point was a non-issue, but I won't
likely live long enough till he withdraws it.
I have no need to withdraw something that I never said; as usual, _you_
are arguing with a strawman.
S
--
Stephen Sprunk "God does not play dice." --Albert Einstein
CCIE #3723 "God is an inveterate gambler, and He throws the
K5SSS dice at every possible opportunity." --Stephen Hawking