In message , at 21:32:14 on Fri, 5 Feb
2016, John Levine remarked:
In the worst case, they could just stop accepting prepaid cards other
than Oyster. The prefix of the card number identifies the type of
card.

That'd be a bad move for tourists as many of the cards which are issued
in foreign (to the tourist) currency are prepay Mastercards. Although
they are not ideal for a party travelling together as you require one
each.

The Travelex card (which offers the usual Travelex stupendously bad
exchange rates) is not contactless. Are there tourist prepaid cards
that are?

I thought the Post Office ones were, but having trouble confirming that.

Also keep in mind that we tourists can and do use our regular cards.
When I was in the UK last year, I used my US issued AmEx card on the
tube and it worked fine, with one charge per day posted on the days I
used it. Dunno how many tourists know about it, but it'd be worth
some posters at the airport tube stations.

--
Roland Perry