If it were that simple, I would wear the tether all the time hands down. However, there is already so much stuff to get entrapped and tangled on the boat that I can't imagine taking another 18' of line and purposely attaching myself to it. My biggest fear is to have the boat going turtle and be tangled and snarled an unable to get free as the boat pulls me under or drags me uncontrolably through the water. Even without tethers, I've experienced a close call this way and in my opinion tethers would make potential for problems worse. They could be more of a liability than the risk of getting separated.

On a monohull, that should ideally remain upright under most all conditions, I wholeheartedly agree to strap myself in. But on a boat that is more stable upside down than rightside up, I have concerns.