Lyx, you've provided another excellent example of the ambiguous types of configuration that exist on the public internet, situations where additional research (in this case a quick look to the domain registrar) would result in a clear understanding.
It's been my experience that every possibly configuration is pretty much guaranteed to exist, somewhere.
That said, I'd like to turn the question around a little bit: Who is in the best position to build a trust relationship with the recipient of ads? I think that webmasters can do this to a certain degree, but that it's the ad networks that could really make the changes.
Picture this - as a recipient of ads, I tell Google/Doubleclick that I don't want Flash based ads. Then, wherever Google/Doubleclick serve ads, I don't get that type of ad. They're already moving on this front (check it out
Overall, trying to shim the webmaster in as a manager between the ad recipient and the ad network is a limited vision approach. And asking the ad blocking tools to support something that the ad networks don't is inefficient.
At least, that's my take.