“The person who consents cannot complain.”
It is a Latin maxim, which means that the person who voluntarily gives consent for any harm to suffer would not be liable to claim any damages for the same. This consent could be used as a good defence against the plaintiff. Hence, the person who himself waived or abandoned his right voluntarily, cannot have any claim over it.
If a person, who went in a cricket stadium to watch a match, gets accidentally hurt by the ball. He cannot claim any damages from the authorities as buying the ticket gives his consent for any harm if suffered.