Losing a GoPro because the sticky mount has failed is not a nice experience. I have been there. Using a leash or tethering system has become a key part of using a GoPro, especially when attached to a kayak, paddle or helmet. Since the release of the Blackout housing and GoPro Hero 4 the usual place to add a leash to tether the camera has gone.
GoPro have removed access to the metal bar that acts as part of the hinge, this was used by many to attach a thin piece of cord although some cases have failed due to this. There are two alternatives to using the hinge that depend upon the thumbscrew on the QR mount.