Yes .. BUT, you probably don't have to engage users to obtain that kind of information. Having a way to determine the click-back ratio (CBR... the % of people that click the browser back button) would probably suffice. Is CBR already a term? - if not I want credit for coining it - he he!
Obviously there are some obstacles to overcome by using something like that, such as browser cache, but all things considered, the error margin would be proportional and thus, sufficient in determining the relative quality of an ad without having to engage the user.
I am wondering:
a) What change in Global average CTR will be noticed by having such a call to action below an ad (ie. will more people click on it to rate it)?
b) In what ways are it susceptible to fraud (competitors fraudulently giving negative ratings)?
c) Contingent on (b), in what ways will Google use the feedback in order to determine which ads are shown?