When you say your rentals are "always paid for" does this mean you are reimbursed for the expense or the rental is third party billed and you have no financial involvement at all?

If you rent with coupons, the receipt will show the full cost and the coupon will show as a deduction. I will use the coupon codes with my clients and they will reimburse the actual cost plus the coupon value as it is considered value that I applied to the transaction in lieu of cash. I used to work for an employer that was Nazi-like in what receipts he would accept or not, so I can understand if you can not get them to agree to this deal.

Anyway, if they do agree, take the reimbursement and rent your friend a car, that is if you are that generous.