A continuing problem for interest groups is the free-rider problem. A free rider is one who enjoys the benefits of a group but does not join it. An example is a worker who does not join a labor union but still receives the union-negotiated wages, benefits, and vacations. Unions, of course, want anyone who receives the benefits to belong to the organization. (This is called a closed shop.) Many states have passed right-to-work laws that forbid a closed shop. Should people who enjoy the benefits of a union be required to join? Can a union be effective if people are not required to join?