No deposit or any other asset held in a deposit escrow account, shall be encumbered or used as collateral for any obligation of the applicant or any other person, unless the applicant obtains prior written approval from the department for the encumbrance or use as collateral. The department shall not approve any encumbrance or use as collateral under this section unless the encumbrance or use as collateral is expressly subordinated to the rights of depositors under this chapter to refunds of their deposits.