Today I'm seeing two kinds of favicons - some are generic - probly what Google fills in if the company doesn't use a real favicon, and some are the actual favicons from the advertiser's site - for example there's a Chevrolet logo in a Chevy ad, and an official state travel bureau is showing the favicon off their site.
So... if they are grabbing the favicons off sites, I wonder if they are spot checking them for accuracy? What if I used a Chevy logo as the favicon on one of my sites (that has nothing to do with cars, and it would ONLY appear as the favicon) and ran some ads, would it show up next to my ad? If I had time for it, I'd test it. Cause that'd be a hole.