Is this now official LW slang?

Only if we need official LW slang for "Have rigid boundaries and take decisive action in response to an irredeemable defection in a game of community involvement". I just mean to say it may be better to use a different slang term for "exit without leaving a trace" since for some "pull a Roko" would always prompt a feeling of regret. I wouldn't bring up Roko at all (particularly reference to the exit) because I want to leave the past in the past. I'm only commenting now because I don't want it to, as you say, become official LW slang.