Google has stepped up its detection and action against clickjacking. Clearly, it's become a bigger problem for it to have to take such action, but this includes filtering to automatically exclude the invalid traffic, and to then exclude publishers taking part in this activity.

Our Clickjacking defenses operate at considerable scale, analyzing display ad placements across mobile and desktop platforms, evaluating a variety of characteristics. When our system detects a Clickjacking attempt, we zero-in on the traffic attributed to that placement, and remove it from upcoming payment reports to ensure that advertisers are not charged for those clicks. Google Takes Action Against "Clickjacking" [adsense.blogspot.com]