It's nothing new. Google has a term called "thin affiliates", which they hate. If you have a landing page that talks about some other guys' products, you will be labeled as thin affiliate and they will punish you the same way they punish doorway page owners.
Another thing I've noticed is that if you start getting big, google will assign a rep for you who will go through your keywords and ads. Then they will slap you hard.
Affiliates can still get away with CB and other sh!tty products as long as you don't spend too much in that account. all you have to do is create a bunch of google accounts from different location, credit cards and IDs and run campaign and don't spend more than $1000 from each account. This won't guarantee better lifetime with google.. but chances are they won't dig and let you get away with many things. This model is sort of proven to an extent ;-)
If you think about review sites, you won't be able to get away. Bottom line, google guys need real publishers promoting in google.. not some bad boys like some of us here. however they like comparison shopping sites, such as bizrate, pricegrabber, etc.