John Band wrote:
The original post was talking about tourists who arrived at Heathrow,
went to the HEX ticket office (ie who would have travelled on HEX
irrespective of the possible cheap fare) and were "conned into paying
for full fare tickets into London".

I would suggest these are not the people that TfL's programme was
designed to benefit, and that I don't see any reason why Londoners'
taxes should subsidise their journey into town...

I note the suggestion but disagree. If I were travelling abroad, and I
had just arrived at an airport, I doubt I would be minded to spend any
time looking for a second ticket office that might be selling more
appropriate tickets than the first one that I came to. I would expect
the first ticket office to be able to sell me what I needed without me
having to have any inside knowledge of the local situation, and I think
most real-world travellers would agree it's a reasonable expectation.

It isn't as if Londoners actually gain anything (other than a perverse
pleasure at the misfortune of others) if visitors pay more than they
need to in such circumstances as this.