Mutual Consent
Both sides say yes, and the yes stays alive: all association between a person and a body is voluntary and based on agreement running in both directions.
Where Consent governs decisions, Mutual Consent governs belonging. A person must assent to the body's Field of Agreements, and the body must be willing to receive them. Neither half alone is enough: a person who assents to a body that has not accepted them is not a member, and a body that accepts someone who has not agreed has acquired a subject rather than a peer.
This is what a Selectively Permeable Membrane is made of. The membrane is crossed only on the basis of ongoing mutual consent — new members enter by it, resources flow in and out by it, and the word ongoing is the load-bearing one. A yes given once and never revisited is how a voluntary body becomes an obligation nobody can name.
Without it, association becomes either capture (you may not leave) or imposition (you may not refuse arrivals). With it, both sovereignties are preserved: the person's, in choosing; the body's, in choosing too. The right of a body to say no is often forgotten in movements that prize welcome — and its absence is how The Parasite enters a commons.
In play, a player meets it at the door: the terms are read, the yes is spoken in their own words where others can hear it, and either side may end the association later in peace. The Welcome a Newcomer and The Way Out movements are the two faces of the same principle.
Also called: Ongoing Mutual Consent Stands on: Consent · Sovereignty · Field of Agreements · Selectively Permeable Membrane Opens onto: Withdrawal Of Consent · Agreement · Welcome a Newcomer · The Way Out · Participation · Covenant In play: door — both directions, every time Sources: Mutual Consent (root page, unmarked) · Sovereignty At Every Scale (the membrane crossed on ongoing mutual consent) · Player+ Modules, Lexicon and Entering the Field · THE DNA OF HEAVEN Part V, The Invitation, and the door (states: Fable synthesis, unreviewed) · lionsberg.wiki: Mutual Consent Open: The root page cites Rules of Participation; the newer canon uses Field of Agreements for the same object. Two names, one thing.