Liability of guardians and trustees: they are liable for GST tax, interest and penalties when conducting business for incapacitated persons. Where a business subject to tax, interest or penalty is carried on by a guardian, trustee or agent for a minor or other incapacitated person, liability for those tax obligations is treated as if the incapacitated person were a major and the guardian, trustee or agent is chargeable with and subject to recovery in the same manner and extent, with all provisions of the Act and rules applying accordingly.