If I remember right Adsense isn't supposed to be shown on error pages, for instance a 404 error page. Is Google really strict about this ? As in, will they ban sites for doing this or just show the backup banner/background-color/PS-ads ? I ask because I have a single 728x90 link unit that's built into my main template & in order to have it shown conditionally I'd have to go through and modify every single one of my application files just to prevent from being shown on the 404 and 410 pages I have running. It seems that my 404 & 410 pages are just showing a solid background color now. And if Google generally just does that rather than banning sites I will skip the effort and just let it ride.