Let's talk about this by using some more common names -- automated blog spamming, forum spamming, link farming. I doubt that even a team of link monkeys could trip this filter with real, humanly acquired links. This is especially true if they were at all trained on evaluating the relevance and quality of linking sites (as any good link monkey would be, right?)
In contrast, there is a situation where a website gets major media attention (mentioned in the NY TImes, for example) and there's a spontaneous explosion of new links. This kind of link growth has its own footprint that is quite different from the kind of forced growth that other types of link growth have -- and it will not cause trouble. Quite the opposite, it can be a significant help.
I also think there is a "link aging" filter where the effect of some marginally trusted links is only allowed to influence search results gradually. The linking sites themselves are going through a trust evaluation.