Historical note: There are conflicting stories about the origin of this term. It has been claimed that it was first used in the Usenet newsgroup in news:comp.sys.apollo during a campaign to get HP?/Apollo to fix security problems in its Unix-clone? Aegis/DomainOS? (they didn't change a thing). ITS? fans, on the other hand, say it was coined years earlier in opposition to the incredibly paranoid Multics people down the hall, for whom security was everything. In the ITS culture it referred to (1) the fact that that by the time a tourist figured out how to make trouble he'd generally got over the urge to make it, because he felt part of the community; and (2) (self-mockingly) the poor coverage of the documentation and obscurity of many commands. One instance of deliberate security through obscurity is recorded; the command to allow patching the running ITS system (altmode? altmode control-R) echoed as $$^D. If you actually typed alt alt ^D, that set a flag that would prevent patching the system even if you later got it right.