The BBC article[1] quotes the 'Mayor's Transport Spokesman' as saying
that Oyster will offer the cheapest fare available; "the only
exceptions are holders of certain national railcards for whom cheaper
paper tickets for travel on national rail maybe available."

I thought there'd been mention of the appropriate discounted PAYG
fares being available to those with their Railcard loaded onto their
Oystercard?

- martin (lamenting the fast approaching expiry date of his last
16-25 railcard)

[1] http://news.bbc.co.uk/1/hi/england/london/8373913.stm