I believe (certainly no expert) that the discount codes are in response to volume guarantees made by a corporation. If the codes were for $/% off, no problem. The issue is when you get into the CDW availability--you have to be employed to get those benefits--had a situation myself where I had an accident in a Budget car soon before I left the employment of KFC Corp in Louisville. By the time Budget was working on the accident, I had changed jobs. They called HR who did not show me as working there, so sent me the bill with a note that Pepsico did not show me working. I had to send it back to my old boss.

Moral is, I guess, be careful