Google, Yahoo, Youtube, and other large content providers don’t push content to the user. The User requests it, through their service providers. The User’s Service Level Agreement is the gating factor on the Quality of Service that affects the transport. If the Content provider isn’t on the user’s ISP network, there’s no real way for the service provider to identify where the content is coming from, other then the numeric IP address. And that address doesn’t need to be associated with the content provider.

So it is rather difficult/complicated for the service provider to bollix up what is being sent if the user is paying for a QoS.