The Ugly Side Of Search

I was recently having breakfast with a well-respected expert in e-commerce. We got on the topic of search engine marketing and search engine optimization and he started telling me about companies that are paying search engine optimization people not to increase their position, but simply to damage and hurt the rankings of their competitors.
Wow. That’s harsh. You’re paying someone not to improve your situation but to lower your competitors. I’d file that one under the lazy, angry and nasty categories. I’m not even sure Sun Tzu would have the stones to write a chapter in The Art Of War on these types of creatures.
I’m curious to know if you’ve heard of companies who will de-optimize someone’s competition and how they do it (don’t worry, I won’t call you out. I’m just curious to see how these slugs market themselves).
There is always an ugly side to marketing. There will always be people who will use their power and knowledge to do more harm than good. I guess I’m just hoping that these people are few and far between.
I know, I’m naive.