Why can't Wei go out alone?

The possible reason why Hellfire can't go out alone is that she is not old enough to get the ability and authority to go out alone. In addition, in order to protect the safety of minors, guardians have the right to restrict minors from going out alone. In addition, the law may require guardians to take care of and supervise minors to ensure their safety and well-being. So Hellway may need to be taken care of and protected at home, instead of going out alone.