In message , at 06:15:30 on Sat, 21 Jan
2012, Adam H. Kerman remarked:
Oyster was originally going to be able to be used for other low value
purchases, such as newspapers and cups of coffee, in the way that Octopus is
used in Hong Kong, but this idea fell foul of banking regulation.

Ah! I wondered about that. Yet, pay-by-cell phone doesn't. Weird.

It may be something to do with cellphone PAYG balances generally being
"non refundable", whereas an Oyster card can be cashed in. As a result
it's more like a "bank balance" than buying "pre-pay vouchers" to spend
at multiple outlets. Gift cards are the same sort of model, you can
redeem them for goods in various places, but the balance isn't really
"cash".
--
Roland Perry