Actually there is logic in it. Most folks don't go past page 3 and so quality control is more about the viable SERPs. There is NO logic in spending time and money playing whack a mole with every little kw stuffing, hidden text scenario. When you run a search engine that is heavily skewed towards backlnks (PageRank) then you can focus most of you energies on link spammers. No links, no rankings… you HAVE TO link spam to rank if yer a black hatter or other rule bender.

As you mentioned the webmasters and site owners are surely going to do much of the work for you as it is in their nature to protect themselves by reporting competitors that are breaking the TOS. What the average site owner doesn’t necessarily understand is link spam (as U have mentioned), so they are suited to the job of reporting the minor infractions. Unless things have changed drastically over the last year, I can’t see the web spam teams focus having changed much on this end.

My main point anyway, is that people need to stop worrying about it… if you come across it, report it, blog about it and move on. There are even cases where NO visible action will be taken and the Google Slap (on the wrist) is a private affair that will never see the light of day. Stop complaining and get on with the business at hand – ranking.