In message , at 16:35:39 on Thu, 7 Nov 2019,
Recliner remarked:

Someone trying to catch HEx from T4 will actually have to start their
journey on a Crossrail train and change at Central, and perhaps again at
Paddington, rather than just taking a through train. They'll be able to
realise their mistake while looking at the route map on the Crossrail
train.

By then they've bought their ticket. On their next trip to England they
may make a different choice.

Yup, HEx may only catch them the once, and probably only in one direction.
Not a good long-term business model.

You are over-estimating the willingness of the sort of person whose
normal policy is "no-one got fired getting a taxi end to end", to start
grappling with London's commuter rail services.

How would they even know (or care) what the cheaper fare was on
Crossrail?

Even assuming that a railhead at one of the Crossrail stations in
central London is a compellingly shorter taxi-ride to their ultimate
destination than Paddington.
--
Roland Perry