I have no problem with the grand theory behind Google's latest anti-spam directions, as revealed by Matt Cutts:
The problem with the first one? Well, consider blogs, comments, and spam. Unless you turn comments off, it's fairly easy to end up with hidden links in a spam comment until you notice it and yank it down. Sure, you can add checking for that sort of thing - but any check will have holes. It could be even worse for a Wiki though. I've seen hidden links worm their way into the VW Wiki, and only noticed them by accident. I think Google needs to be careful about enforcement here, or a lot of innocent sites could get snagged.
Paid links can get even dicier, when you look into it. Yes, PayPerPost is the obvious "bad boy" of this genre of links. But what about standard business practices? If company X is my partner, and part of our contractual arrangement is to share links on specific pages, does that count as paid? It might, depending on how you classify it. There are plenty of gray areas in that category, so if Google wants to deal with them, there better be guidelines.