Happy with contactless - now everywhere??

[MikeWh]

But the limitation is that a CPC can't be used to make payments above £30. No bank would allow a (potentially stolen) card to be used without a PIN for a trip from Plymouth to Aberdeen or Inverness!

With a contactless card, you have to make a non-contactless transaction with PIN every so often or contactless stops working. How does that work with TfL ticket barriers/buses?

£30 maximum and make a PIN transaction every so often are both features of the retail model of contactless payments. TfL designed, built (in partnership with the banks) and use the transit model. This is different in a number of ways. The first touch generates a behind the scenes authorisation. If that fails then the card will be blacklisted which means that it can't be used to start a new journey after that point. You will be let out from your current journey however. All the journeys in one day are added together and form one charge at the end of the day. This is not limited to £30. You will never be asked for a PIN at a gate or validator because at that point the card is making a zero value transaction so it won't trigger a PIN check.