IMO they will do this out of necessity soon enough.
This will mean advertisers can't count exact hits to their ads (or at least would be foolish to do so) so they will probably have to employ some kind of web crawler or HIT services to randomly sample the sites who are supposed to be serving their ads to make sure they are.
But eventually the blocker technology will become much better at blocking page element ads more easily and automatically. Then I guess they will have to think of something else.
This will mean advertisers can't count exact hits to their ads (or at least would be foolish to do so) so they will probably have to employ some kind of web crawler or HIT services to randomly sample the sites who are supposed to be serving their ads to make sure they are.
But eventually the blocker technology will become much better at blocking page element ads more easily and automatically. Then I guess they will have to think of something else.