If a TV station uses material from a secondary source, it's good professional practise to give on air credit, even when use of the material does not come with a 'must courtesy' clause. Unauthorised usage can attract a lawsuit. But care should be taken not to give undue credit, for clips from YouTube.
Most broadcasting houses have subscribed to various news agencies or wire service, because it's more cost-effective to source, especially video footage from them, than deploying crews to gather the same material from far-flung areas.
Local TV channels have also increasingly been getting their material from YouTube, due to the abundance, availability and ease of accessing desired footage.
But what if the video is uploaded to YouTube from a primary source, with or without authorisation, and then a TV channel downloads the same material and uses it in its broadcast. Who should be credited?
Is it the primary source, in this case 'Sky Sport' or YouTube?
It seems pretty naive for this channel to 'Courtesy YouTube' for the clip.
And 'Sky Sport' retains the right to make matters ugly for the TV station, if broadcasting rights have been infringed.