On two basic properties of equilibria of voting with exit

We consider the problem of a society whose members must choose from a finite set of alternatives. After knowing the chosen alternative, members may reconsider their membership. Thus, they must take into account, when voting, the effect of their votes not only on the chosen alternative but also on the final composition of the society. We show that, under plausible restrictions on preferences, equilibria of this two-stage game satisfy stability and voter's sovereignty.