[2] A cord or rope tether may reach its breaking strength and fail.
Outcomes can include an injury or fatal fall, and damage or loss of life to personnel or bystanders caused by backlash of the ruptured segments.
Some safety harnesses are used in combination with a shock-absorbing lanyard, which has break-away stitching designed into it to prevent material failure and regulate deceleration, thereby preventing a serious G-force injury to the user when the end of the rope is reached.
Designed-to-fail safety links are sometimes used to prevent excessive tension in a tether involved in towing objects, such as sailplanes.
The signal may be electrically generated, or a physical device such as flying a flag.