In message , at 22:11:42 on Sat, 2 Mar
2013, John Levine remarked:
AFAIK, the problem is in getting foreign card issuers to buy into the
feature whereby the cardholder is *never* asked for a PIN (on TfL or
other transport operators), which requires some new flag setting as well
the card issuer dealing with fraudulent purchases slightly differently.

Depends on the issuer. On contactless cards issued in North America,
I've never been asked for a PIN or signature on charges under $25,
which even at current prices should be a rather lengthy bus trip.

Do you use the card exclusively for contactless charges under $25?

Making a conventional transaction, or a contactless charge over $25 with
a PIN, will both reset a transaction counter on the card, and it will
start counting up again (to an unpublished total, which can vary by
issuer and application, but perhaps commonly ten[1]) at which point a
PIN will be asked for.

I'm also reminded that the TfL scheme apparently won't accept pre-pay
pay-wave cards, which are more common outside the UK than inside.
Although (being a bit of a collector of this kind of thing) I do have a
UK-issued one and I'm tempted to try it next time I'm in London. The
risk, of course, is that the account is dry, something which can't be
checked in real time while you are boarding a bus.

[1] And which I've seen reports saying is set to "one" by card issuers
in some countries, which is a reason for TfL to be cautious in what
they promise. I've also seen reports that say it's set to 4 x $25
(or whatever that card's limit is), but I'm sceptical because I
don't think the card keeps a monetary transaction log.
--
Roland Perry