It is true that there is an issue of how to have balane of free will on Earth. The answer though, is in exactly the shared understanding of free will and what is needed to be present in order to have free will.
A voluntaryist society is one where everything is done voluntarily - which is part of what is needed. The other part is the designation of the Earth itself as having rights and thus a true set of universal rights for humans and animals which reflect their right to freedom. This totally conflicts with the capitalist idea that we can just 'buy' the Earth, but it is the only possible solution to the madness we are experiencing as far as I am aware.