Under the compulsion of formality, complex legal-administrative codes have no option but to make space for the future.
FinCEN’s crucial (and still incompletely digested) guidance note on virtual currencies, issued March 18, 2013, clarifies in a footnote (#2):
FinCEN’s regulations define “person” as “an individual, a corporation, a partnership, a trust or estate, a joint stock company, an association, a syndicate, joint venture, or other unincorporated organization or group, an Indian Tribe (as that term is defined in the Indian Gaming Regulatory Act), and all entities cognizable as legal personalities.”
There’s plenty of room already for almost anything to slither in. (Follow the DAO.)