As a military retired person who does and oversees a lot of travel at my current job, Marriott lost most of my business and a lot of my company business when they stopped allowing retirees to receive the military rate. It is much cheaper to stay elsewhere now, even though I would prefer to stay at the Marriott - the Marriott cost now exceeds what my company is willing to pay for lodging. I think this was a terrible move by Marriott and is costing them a lot of money, because military retirees can always go somewhere else that still gives them a military discount. It may not be as nice, but most retirees are not rich and they go where they can afford. Marriott just priced a whole customer base away from their hotels.
Most rate rules do not specify AD only...only that a government issued ID is required. I normally find the AAA or senior rates acceptable, though not normally as good as government rate, but I don't have to be concerned with being challenged by the front desk. Not the way I want to start off any stay.
I hear you nuhusker, but in my experience at least 90% of the time these front desk folks don't ask for any proof. Not bad odds. I have presented my Army Discharge Card a few times and it has been accepted. I have also presented my Deputy Sheriff (retired) creds and they have been accepted (it's something about the badge, I guess).