Originally Posted by
EZEDoesIt
The receipt shows the full price of the ticket and the breakdown of the payment.
I don't see what's so unethical about using non-credit card forms of payment. You don't know where the OP got the voucher from. Maybe it's just credit for a cancelled flight that he wants to burn before expiration.
Even if it was a DBC voucher I still don't see the ethical issue. The OP was paid compensation for their trouble - it isn't "free money" as they gave up their time.