This is interesting, if you search for [oil spill] in Google, you should see an ad for BP. The display URL on that ad is www.BP.com/OilSpillClean but if you click on it, you are taken to YouTube.com and not BP.com.

This clearly goes against Google AdWords display URL policy that reads:

It seems like BP is getting away with this either through some sort of bug in Google’s ad system or they were given a special consideration for this?

Here is a picture of the ad:

If you click on it, you go to YouTube.com, specifically to the BP channel on YouTube.com.

Forum discussion at WebmasterWorld.