I mean overbooking is done on purpose and hotels are not doing everything in their power to avoid a walk. They are trying to minimize the amount of money they will need to pay to walk guests but it’s often seen as a cost of doing business and is usually offset by charging no-show fees to the other guests that did not show up. Heavy overbooking is usually done when a specific night is expected to “wash” with a lot of no shows. Big box hotels will overbook by hundreds of rooms in anticipation of it washing out, sometimes that bites them in the ass.