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Why does everyone think that Google is so dumb that they won't catch on to all of this sneaky stuff?
As someone noted above - all it takes is one complaint about the popup and you are disabled.
Personally, I detest popups in any shape or form, regardless of who or what they are advertising.
The best way to approach this is to create new pages, the pop-up info and content all on the same page nicely merged. You could probably do this with a programming language such as Perl quite easily by marking start and end of content with specific comment tags. Then you could point Google AdWords to a this specific page such as:
Then your 'ordinary' visitors get the popup, AdWords users do not (but still get the info) and you do not risk a ban for cloaking.