Good topic. Since I am ineligible for corporate or government rates, most of my business or leisure travel is booked online at AAA rates. It usually presents the best value.
After booking, I'll call Elite Reservations or the hotel directly with specific requests and ask about comp upgrade availability. Usually the front desk knows if a trade show, wedding or group event will impact availability weeks and/or months in advance. I won't even attempt to compete and rebook elsewhere even if the rate is a little bit higher.
While time consuming, the practice works for me. On occasion, multiple calls are needed because availability can be dynamic.
Although there have been some posts on this board supporting better perks, etc for full fare customers, there's nothing in the Marriott T&C about consideration for upgrade having anything to do with the rate you pay. I personally have never had a problem with this, and get some type of room upgrade nearly every stay, so I don't anticipate this being a problem. In addition to the advice already given, you might consider calling platinum reservations and ask them to add an upgrade request notation to your reservation. At least then the hotel gets advance notice/request so "maybe" you won't need to replow that ground at check-in. Good luck and safe travels.
I often wonder the same thing. Rarely am I ever asked to show my AAA card, but I don't seem to get any special room. I HAVE noticed, however, when checking room rates (both special and supposedly discounted) online that the AAA rate is often much higher than the regular rate. In that case, maybe there is a better room involved.
Being old (over 62) the Marriott Senior Discount is often the most economical of all the non-affiliation and restricted rates.
It's pegged at 15% off the rack and when available, the weekend rates. ID's will be checked, except in my case, where the gray hair and wizened visage make it clear that I qualify.
I am reminded of the notice at a badge room in my Army days, which read: "If you want a better photograph, bring a better face!"