Read the TOS. There is a part that sais that you should not use the adsense code inside of popups.
You mean fake traffic? If so the problem for Google is not the fake traffic, but the fake/invalid clicks
found this about pop-ups/unders:
"No Google ad or Google search box may be displayed in a pop-up, pop-under, or in an email."
and this about redirects and ad networks:
"Webpages containing AdSense code may not be loaded by any software that can trigger pop-ups, redirect users to unwanted websites, modify browser settings, or otherwise interfere with site navigation. It is your responsibility to ensure that no ad network or affiliate uses such methods to direct traffic to pages that contain your AdSense code."
My take on their answer is that sometimes you get money for impressions (some ads are paying CPM impressions) and they would not like you to inflate your traffic because you actually inflate your ad impressions and you increase your revenue and they charge their customers for traffic that has not even looked at their ad ...