I think it is quite important to distinguish between "courtesy" and "legality".

As far as I know, nobody can get sued for recording another artist's compositions without their express prior permission, and as long as the appropriate royalties are paid then there is bugger all the composer can do about it.

Or a meringue ? (Billy Connolly joke for the non- Scots ...)

It would however be a gross discourtesy to the composer to embark on such a course of action, but that is all it would be, just discourtesy. Or a meringue again ?

I personally think the whole YouTube thing requires a rethink on the part of the legislators and the copyright owners.

I believe that a small annual subscription to view the music videos on the site wouldn't be a bad idea, and out of this fee composers could receive an emolument proportional to the number of times the video had been viewed.

Still awaiting Richard Bridge on the "copyright of performance " issue (sic)...