Haw. Code R. § 14-52-81.1
If any participant receives one or more payments or reimbursements under the plan that are not for a permitted benefit, the participant shall indemnify and reimburse the employer, plan administrator, and third-party administrator for any liability it may incur for failure to withhold federal or state income tax or social security tax from the payments or reimbursements. However, the indemnification and reimbursement shall not exceed the amount of additional federal and state income tax (plus any penalties) that the participant would have owed if the payments or reimbursements had been made to the participant as regular cash compensation, plus the participant's share of any social security tax that would have been paid on the compensation, less any additional income and social security tax actually paid by the participant.
Haw. Code R. § 14-52-81.1