Mere membership of a banned organisation will not make a person a criminal unless he resorts to violence or incites people to violence or creates public disorder by violence or incitement to violence.
….. that mere “advocacy or teaching the duty, necessity, or propriety” of violence as a means of accomplishing political or industrial reform, or publishing or circulating or displaying any book or paper containing such advocacy, or justifying the commission of violent acts with intent to exemplify, spread or advocate the propriety of the doctrines of criminal syndicalism, or to voluntarily assemble with a group formed “to teach or advocate the doctrines of criminal syndicalism” is not per se illegal. It will become illegal only if it incites to imminent lawless action.
Download full judgement here as PDF – Arup Bhuyan Vs- State of Assam – Banned Organisation
Or get it from this link. helddis.aspx