nomis5 - 11:26 am on Sep 6, 2011 (gmt 0)
Seems to be a basic step to check that the ads are placed according to the TOS. Maybe they can automate the first step, reject some at that stage and only then manually view sites who have passed the first stage.
It must also be easier to review a site if blank ads are there already.
But it will impact the user experience if there is a large blank box with nothing in it, even if the colours are OK.