You can create a direction for Google AdBot specifically not to visit certain parts of your site.
Google does not like affiliates from the perspective that the site has been created with affiliate business in mind. So Tedster's claim stands that you have a site about something you "love" or "do", and then you figure you could put affiliate links onto it.
On another side, my experience tells that sites with QS of 10/10 for long time get slapped with manual review and switch to 1/10.
I argue with this as it is obvious that the system was not cheated on, but good content has been provided and yet Google's employee has determined that such content already exists (on authoritative site) and therefore your site sucks and nobody needs it.
In some cases this is right, but in others where affiliate site provides a unique reviews, or unique coupon codes and other discounts, QS switch should not be the case.
In overall, Google AdWords does not have much sentiment when about affiliates, period.
They even don't give any kind of specific support like dedicated rep or anything similar. I run tens of accounts and have lost reps more then two years ago even with spends that are extremely high on regular bases. At that time I had two reps (day to day, and senior one) and then BAM - no more. After that, I was approached several times by AdWords with ideas about how they cold help, but as soon as they hear about my business concept, they're gone. If I run an agency that does service for clients, it would be OK. Now, what's the difference?