how can screen resolution come into it?
if the ad ratio is okay for a 1024 res, but not okay for a 800 res (which is easily possible), are they going to mark the 1024 res down too? there would be no reason for it.
so they'd have to show different SERPs for people using different resolutions, which isnt going to happen.
if they're going to mark sites down for this, then it would have to be on a ratio of the entire page. that is how their bot would see it as well