(1) A spendthrift provision is valid only if the provision restrains both voluntary and involuntary transfer of a beneficiary’s interest. This subsection does not apply to any trust the terms of which are included in an instrument executed before the effective date of this code.
(2) A term of a trust providing that the interest of a beneficiary is held subject to a spendthrift trust, or words of similar import, is sufficient to restrain both voluntary and involuntary transfer of the beneficiary’s interest.
(3) A beneficiary may not transfer an interest in a trust in violation of a valid spendthrift provision and, except as otherwise provided in this part, a creditor or assignee of the beneficiary may not reach the interest or a distribution by the trustee before receipt of the interest or distribution by the beneficiary.
(4) A valid spendthrift provision does not prevent the appointment of interests through the exercise of a power of appointment.