I've tried googling for a previous answer to this but couldn't find
one...

I have an Oyster pre pay card, which suits me very nicely since I
normally make 2 bus journeys a day, with very occasional tube
journeys.

A couple of times recently, I've got on a bus (at least once it was a
108, may have been both times) and the Oyster reader has been broken
(showing red light). The driver has either just waved me past, or
completely ignored me. So I've had a free journey.

But what would happen if an inspector got on? No problem for the
Oyster travelcard users, but presumably for prepay he'd check my card
and find no record of a recent use on this bus route. So would I be
liable for a penalty fare? Should I pay the cash fare to the driver
even if he doesn't ask me to (unfair on me, as this would mean 30p
extra for the bus company)? Or should I have a stash of saver tickets
for this purpose (which defeats the object of Oyster cards - paperless
ticketing)?

My view is that if the bus sets off with a known duff reader, then
that's their problem and they should accept the consequent loss of
revenue. But I'm not sure if this would "stand up in court"...

So I'd appreciate any suggestions you have!

cheers

Graham