It's actually particularly relevant because someone seem to be making a serious effort at one using, naturally, Bitcoin: Sanjuro's "Assassination Market" (see http://www.gwern.net/Silk%20Road#future-developments for details).

It's hard to tell if AM's a scam or not by the nature of assassination markets, which turns out to be an interesting observation, IMO - it never occurred to me, reading the original speculations, that assassination markets would be so much harder to bootstrap than drug markets like Silk Road.

This long predates Bitcoin, although BTC gives it a new immediacy. Assassination prediction markets like this were a topic of discussion on cypherpunk mailing lists back in the 1990s.

It's one way to give anonymity (or strong pseudonymity) a political dimension, positive or negative.