I have a few friends who work at google and this seems like common knowledge. In conversation though it wasn’t nefarious, they just thought it was unavoidable and relatively constant so they reasoned that the inefficiency is built into the price. When I asked that they did to combat it, they weren’t aware. Hopefully this lawsuit shows the lengths that google goes to to reduce ad fraud.

But it seems likely to not be too effective. It just seems like the incentives aren’t there. It’s like when magazines estimate their readership, there’s no regulator checking their numbers so it’s just something buyers have to accept.