Shafer did it on the Tommy Bahama boat by having the tether free to move on a guide that ran from the front beam to the aft, and from port to starboard as I recall. The tether, which attached to the trapeze harness only had to be long enough to stand. From the water, the stern of the boat was still in arm's reach.
I see a chicken line, like what Shafer had (and we use), and a tether as different things. The prusik knot on a leader strung between beams works well to prevent waves from knocking you off the boat while on the wire...but we don't stay hooked into that when sitting on the deck or tacking/gybing. I try to configure mine with a quick release so you can get out of them in most situations. It's use is a little different than what monohullers commonly think of as a "tether" but perhaps if the OAs see them as a similar item we might find some common ground.
