With Oyster there is this new scenario that hasn't as far as I can see
occured before in transport ticketing - to have a valid ticket fore the
whole journey a passenger must perform the correct action at the end of
that journey i.e. touching out. ...

I believe there are some commuter type bus opperations somewhere (US, I
think), where in the evening peak, everyone boards at the start, and
pays their fare as they alight, so that the huge queue to pay on
boarding is avoided (because you all board together, but alight along a
spread out route).

Not only commuter. I don't know if it still is, but it used to be the
rule in Seattle on the ordinary city transit buses that on an outward
trip from the city center you paid on exit. Payment on exit has also
been used on the Rockaways line of the New York subway, and on some
parts of the Boston transit system. In Toronto, some TTC trips outside
the city use it. These last three cases have all been done as a way of
implementing fare zones without requiring people to produce a ticket
both on entry and on exit.
--
Mark Brader, Toronto,
"Have you ever heard [my honesty] questioned?"
"I never even heard it mentioned." -- Every Day's a Holiday

My text in this article is in the public domain.