Google has a long history being reactive against fake clicks. Google developed rules against fake clicks to counter schemes publishers used to exploit its advertising platform.
Publishers were allowed to use colors and fonts to style ads until they were prohibited. This resulted in up to 50% clickthrough rates and revenue paid to the publisher.
Another example of Google being reactive is the person who, in the early days, was well-known for his click bots and partnered with people to share revenue-sharing ad clicks. It was a very successful partnership that allowed this person to continue doing it for quite some time.