I agree with Vincent re: this.
YouTube is well within it's rights (at least in the US) to NOT do this. From a legal standpoint, I would imagine that if they started to do this for certain content providers they then would be liable to do it for all, and there is no realistic way for them to do so.
Having said this, I find it interesting that YouTube decided to payoff some of the large TV & Movie studios so they would agreed not to sue Google for 3 years for allowing infringing content to be posted. I think Google perhaps recognizes that if they don't play nice with the big providers they will be stuck having to constantly pull posted clips. It may be cheaper (and a better business model) for them just to pay off the big guys and not have to deal with it. Though, really what Business model does YouTube have? I believe so far all they have been able to do is generate huge losses.