I used to work detecting ad fraud. Publishers would do bad things, call in, and try to get their account rep to get details.
Obviously I can't say "of the last 2500 ad clicks zero of them had any mouse movement over the ad before the click event" because then the publisher obviously just fixes their fraud software.
This isn't specific to Google or even advertising. Every company has figured out when dealing with abuse and fraud sharing the minimum amount of information is beneficial to the health of the ecosystem as a whole.
Obviously I can't say "of the last 2500 ad clicks zero of them had any mouse movement over the ad before the click event" because then the publisher obviously just fixes their fraud software.
This isn't specific to Google or even advertising. Every company has figured out when dealing with abuse and fraud sharing the minimum amount of information is beneficial to the health of the ecosystem as a whole.