>>ColinW+(OP)
How can a bot create fake impressions? When a bot (or just a simple program) makes a http request he fetches the raw html code only. AFAIK if you don't actually render the html code in a browser or requesting all the contents afterwards again with http requests (like GET ad.jpg, GET logo.png etc.), no google ad server should be hit. Now you could argue that bots could inflate the popularity of a website and therefore the cost to run ads on it. But I guess websites that show ads have most likely google analytics running, one of the only ways Google can actually calculate the popularity (besides Google Search and maybe Chrome history). So it should be no problem for Google to exclude bots from the popularity calculation by analyzing traffic. Maybe I am just missing something, I am also no ad expert at all.