Of course we can also think of ourselves being born into churches that levy high
costs for exit and some of us do in fact jump ship and hand in our passports.
From a sociological point of view the voluntary/non-voluntary distinction
can be tricky. But as a legal matter, the distinction is somewhat easier to
maintain: on the one hand, while living within a state, with very few exceptions,
we may not opt out of legitimately enacted laws; on the other hand,
associations may not use coercion and force to retain members.