For a potentially positive version of this, see my blog. I deliberately assume that the reader is an advocate of cryonics, despite an awareness that some (most?) potential readers are not already interested in advocating cryonics. My working assumption is that this will influence a substantial portion of fence-sitters to define themselves as cryonics advocates in order to resolve the cognitive dissonance -- more so than e.g. directly arguing that people should become cryonics advocates.

I wouldn't be doing this if I thought people are likely to become cryonics advocates by rational processes or that being a cryonics advocate is irrational. Rather I see it as a form of defense against the dark arts previously being employed in favor of the status quo (i.e. ignorance and apathy on the subject). I wouldn't want to see this sort of thing become the Less Wrong norm though, as it would confuse people. Less Wrong is an environment in which Dark Arts are combated routinely and directly, indeed doing so is its primary focus.

But to abstain from the dark arts in my little advocacy blog would require shifting the focus to epistemic rationality itself and losing most of the potential audience, who would find it boring and uncompelling. From an instrumentally rational perspective it just does not make sense in the situation. Fighting fire with fire (or ice with fire, if we want to improve the metaphor) makes more sense.