Colin Rosenstiel wrote:

A Tramlink validation allows you to open the exit gates at
Wimbledon, but tram journeys do not require touching out, so there is
no revenue implication.

The manual gate validator will regard a touch as starting a new
tube PAYG journey.

But what is its purpose by the exit gate?

I presume so that people with pushchairs/cases/etc... from the tube can
touch out.