Marriott has used the term "no blackouts" to imply they don't allow either blackout dates or capacity controls. Of course, now they don't impose meaningful restrictions on either.

The flip side of this is that many Marriott properties are still pretty good about offering award rooms, which is why we can still sometimes get outsized value (>1 cpp) on award stays. Even at Hyatt, where the rules are much more member friendly, the properties that don't participate in good faith have found ways to game the system (unreasonable minimum stay requirements being the principal means).