For an organisation like the BBC I personally think it's pretty shoddy to make use of open source stuff and then not at least let us download it and use it. Not saying we need to see *their* code per se.
Then again what closed commercial software DOESN'T use open source stuff somewhere in it.
I'm just jealous because I'd love to have a play and see if it's useful.
The BBC are quite careful about releasing stuff that could be seen to 'distort the marketplace through public subsidy'... There are commercial companies who would accuse the BBC of that if they released some in-house developed products as open source (or commercially)
The BBC DID pay for some development to be done in ffmbc (the broadcast fork of ffmpeg) that was Open Sourced - so it has ploughed stuff back into the community. BBC developers have also added additional functionality to ffmbc (some of which has found its way into ffmpeg) - adding BBC intellectual property that is now out of patent (Weston 3-field deinterlacing and some frame rate conversion based on BBC 80s standards conversion research)
SVT in Sweden has had potential litigation issues with both Viz and ChyronHego accusing them of the same with CasparCG - though SVT seem quite confident in their position.
As for it being previously 'publicly available' - I'm not sure it ever was officially. The BBC Editing Site may have been available to anyone who found it - but the content on it may not have been free for them to use. (The equivalent of leaving your front door open not meaning people can come into your house)