301-72.203—When may we limit traveler reimbursement for a cash payment?
If you determine that the cash payment was made under a non-emergency circumstance, reimbursement to the traveler must not exceed the cost which would have been properly chargeable to the Government had the traveler used a government provided payment resource, (e.g., individual Government contractor-issued travel charge card, centrally billed account, or GTR). However, an agency can determine to make full payment when circumstances warrant (e.g., invitational travel, infrequent travelers and interviewees).