Etiquette is socially accepted forms of behavior, agreed upon by the members of a community.
Ethics involves morality, the nature of right as determined by a group or an individual.
Among these there is a very firm one saying one should never reveal another person as a Witch without their permission. However a person who has revealed themselves publicly as a witch shouldn't complain. Ethics can be fairly easily agreed upon in the general pagan community. Anything that puts someone else in an embarrassing or dangerous position is unethical. We all make mistakes at times, but we try to act in a manner consistent with our ethical code.