d wrote in
:

If you want BAA to offer the concession to their passengers as
well, who do you propose should foot the bill and why?
What bill? Did BAA run extra trains or otherwise incur any extra
costs?

The money they lose by people who are using the HEx to get from
Heathrow to Paddington, as the service is intended, buying
travelcards instead. If everyone gets to take advantage of the
concessions being made to TfL ticket holders, that's not fair on HEx,
who are offering a helpful service to otherwise stranded members of
the public. HEx didn't instantly become part of the underground that
weekend

So are you saying that people who were aware of the concession should
nevertheless pay the HEX ripoff fare in order to boost BAA's profits? Surely
it is ever passenger's right to pay the least fare that they can legally get
away with.