The Google Ads policy on "trick to click" in image ads will change sometime around 20 August. The policy is changing to prohibit all black, white or transparent background ads without borders. The change will affect all countries. We made this decision for the benefit of the user and publisher experience, as well as the enforcement of consistency. We'll send notifications to affected advertisers.
After the new policy goes into effect, the policy description will be updated to reflect this change.
(Posted in August 2013)