If we think the war our current society work is so important, and if we recognize that we use coercion as a tool to get it, then how much of our lifetime labor would we personally offer to contribute to aliens who showed up with credible promises of voluntarism as a product - something that would magically wave away all the problems of adopting voluntarism. A year? More? Less? I would propose that the smallest value that the answer would take is equal to the time they will spend earning money for taxes in their lifetime that they wouldn’t need to pay in this virtuous, equally functional voluntarist world. It would go up from there as a function of the perceived moral value of living in a non-coercive society.