If you added a true/false field to a content type and its default state is false, you would want to also check for NOT EXISTS, though, to return the full set, as ACF won’t autopopulate the false state for all posts, no? So usually if I’m working with a true/false field, my meta query is looking both for posts with the 0 value (false) in the key or posts where the key doesn’t exist at all.
