Legislation in Saskatchewan, Manitoba, Ontario, and Nova Scotia expressly or by judicial opinion has been read to allow for what are informally known as national "opt-out" class actions, whereby residents of other provinces may be included in the class definition and potentially be bound by the court's judgment on common issues unless they opt out in a prescribed manner and time. Court rulings have determined that this permits a court in one province to include residents of other provinces in the class action on an "opt-out" basis.