MIG wrote:

Why is it more reasonable to assume that someone who forgets to touch
out of the DLR immediately heads for Amersham, having advanced
purchased a ticket from Amersham to Stoke Mandeville, just to try to
avoid paying the outer zone part of the LU journey? (Assuming there
are gates at Amersham, but if there aren't,

There are.

it's the previous
suggestion. Install gates so that there aren't any places out of zones
that someone could escape through.)

Right - so TfL should install gates across the entire GB network? Staying
entirely within the gateline the number of destinations outside London is
huge.

And a lot of stations just aren't physically designed for gates. Try, say,
Motspur Park where the entire station is on the island platform (and the
bridge to it doubles as a route over the rails). Access to the platform is
before the ticket office. There doesn't seem to be any way to physically
install side gates.

Or for some better examples, my local stations of Wantsead Park and Forest
Gate. The former is located on a viaduct and each platform is accessed by
stairs from street level within an arch over the pavement, with no current
ticket office. Where would you put the barrier? Or Forest Gate, where even
the ticket inspectors have to effectively split the "fares only area" into
three - platform 4 (only accessible by going out onto the street), whilst
the corridors and junction for platforms 1 and 2/3 don't leave an easy spot
to create a row of barriers (short of putting the ticket office behind the
gateline!).

This is not as important as making it possible for people to combine
paper and Oyster without jumping through ridiculous hoops.

I agree - it's the price of paper extensions and the lack of one day
travelcards being available on Oyster that I find to be the biggest
irritant.