Adwords For Adsense Sites?

I've been seeing a few pop up lately in my industry. Doesn't make much sense to me because it looks like a wash and some losses in terms of how much they're paying for adwords and what they may be getting out of adsense revenue.

What's the real deal here? Am I missing something? I suppose if they click on an adwords banner, the surfer may be inclined to click on more than one adsense ad when they spend time on the site?

[edited by: martinibuster at 4:36 pm (utc) on Dec. 4, 2004]
[edit reason] edited for "oops" [/edit]