To be fair, he didn't ask if they were any good. He just wanted to know if there were any best practices related to owning a fixed gear. Aside from the advice to not buy one, does anyone have any other advice?

Cheap fixed gear bikes are perfect for people who want to get into fixed gear riding, without spending a whole ton of scratch. It will at least work long enough for the guy to know whether to invest any more money in a better bike. What's the big deal?