wilderness - 4:58 am on Feb 17, 2010 (gmt 0)
I can't imagine they're too happy when sites block them on the assumption that they're thieves or pirates.
Neither Google (or any other SE), or visitors are required to be provided with an explanation for denial of access. More often than not, the visitors browser will simply return the browsers own default 403.
I limited non-NA traffic to two websites for more than ten years, including on the translators, SE provider tools and many other file utilities.
And all of this visitor restriction/denial without hindering my SERP's or even slowing down the crawling by the major SE's.
In all fairness, and frankly to be honest, I've never used Google Adsense or any other type of google ads on my sites. As a result, I'm without any capability to provide insights on how this access restrictions would effect these programs.
Additionally, the hogwash about the WWW being a community of free and unrestricted access is pure hogwash.
The WWW is served with a variety of uses and even closed networks with no public access at all.
"Extranet" and "Intranet" are good reading topics for those who may not be aware of such things.