TKD wrote:
I think the main reason is that some people live in zone 2 north - say
Kentish Town - but work in zone 2 on the other side of zone 1 - say Canary
Wharf. By buying a zone 2 paper weekly they hope to avoid the fare for zone
1 every day, which with Oyster they can't do;

They can't do it with paper tickets, eitherm when the Revinue Protection
crowd get ahold of them.

(Unless they - say - use the NLL to avoid zone 1 properly, but then
the oyster card won't charge them)

On the day prepay launched enough people with season tickets accrued
negative balances for the media to report it as a bug.

http://news.bbc.co.uk/1/hi/england/london/3422051.stm

There was of course no bug. All of those people did not have zone 1 on their
travelcards and for the first time the system was able to catch them out.

How interesting. I'd heard those reports and kind of dismissed them as
rubbish journalism stirred up by the Lib Dem candidate for Mayor, Simon
Hughes, who never missed a chance for a dig at the Mayor Ken and didn't
let such trivial things as facts get in the way!

That's fascinating to hear the real reason behind the 'Oyster bugs' was
the system working properly (and catching people out) rather than a
system problem. It's not called a smartcard for no reason at all! Is
your information from an authoritative source?