What determined whether a Marriott hotel can call itself and qualify as a convention hotel? Specifically, I am trying to find out whether a hotel will honor the elite guaranteed 4pm checkout, which resorts and convention hotels are not bound by.
If you have a specific hotel in mind, I would call and ask and/or search the late checkout thread. Even at non-convention, side of the Interstate limited service Marriotts, late checkouts are often thwarted by local desk clerks. IME, the bigger & more rooms available, the better your odds.