I wasn't given a vote when we decided to hand out all of the land and resources to them in the first place, so I hardly see how the system as it stands is in any way voluntary.

Do you think most wealth is from land? Is that who the UBI taxes would come from? Would it be funded by a property tax?

If we made it voluntary, almost no one would volunteer, certainly not enough to be viable. Taxation and the rule of law aren't opt-in for the same reason.