Re: No it won't.
"It flags legit sites because they have an ad banner that is hosted on the same provider as a dodgy ad."
Good. They have my wholehearted support on this one. Just maybe the owners of said sites will get pissed off with the traffic loss and dump their shite ad peddlar in favour of one who's prepared to vet the shit they pump out before they do so and will insist on hosting the material themselves rather than linking to it, so they know damned well they are serving what they vetted.
The moody ad pushing tossers richly deserve to go bust and this might just be the lever that causes it. Bit of a shame that one of the major offenders here is DoubleClick owned by, er, Google. I wonder if DC ads will have an exemption* here?
*Which would be evil of course.....