That's a very Google idea, and it's a bad one. Malware distributed through Google's ad system has been an ongoing problem.[1][2] Letting Google's advertiser customers inherit Google's trust is a terrible idea.
Google needs to put all their ads in IFRAME sandboxes. Tightening up on what an IFRAME can do wouldn't be a bad idea, either. No popups, no self-starting video, no absolute positioning outside the clipping pane, no expanding the frame size...