If one would be a target of automated spammy link attack - let's say a competitor would order 100 spammy links a month for example 3 a day - how could one defend against this kind of attack? (I'm not in such situation, just speculating)

What I'm wondering is how easy it is really to get to top at some more obscure search term by just using nasty black hat tactics. I'm also wondering if this is actually the easiest way to get top of search results. If that is the case than it's really alarming IMHO.

automated disavowing, maybe? Sucks, but may be necessary.

But how could you know what links are real and what are not if not even google knows it? If you are trying to get legin backlinks at the same time then this would be almost impossible.