yeah but that's the point: 'innocuous ads' have never been tested on the net.
it started as attention seeking eye-knifes, transitioned into the sex sells & hardcore gamer crap, and ended up as 'legal' reverse mortgages/fake charities/malware/data-harvesting.
I think it's safe to say that experiment has been tried.
Yeah, but many humans have a way of thinking this time will be different!
And it never is. Not just about ads, either.