Two quick items I have considered if I do more serious distance stuff (like Tybee)

- Tether with float that is attached to the end of the boom (like your protest flag). With about 30' of cordage. That way, if one of the sailors is separated, the other can release the float with the line, which will drag out behind the boat. Circling the sailor in the water should eventually put the line within reach. It's basically a smaller version of a monohull MOB system

- In lieu of a tether, if you have the snap thingy on your harness hook, it should stay connected to the dogbone unless you unlock it. If you're hooked in the whole time (even not trapped), you should remain connected with the boat. In the unlikely event the trap line breaks, you can hope the shock cord is strong enough to hold you. I upgraded my shock cord thickness AND length (zig-zag under the tramp), and it DID once drag me along after the dogbone broke off the swedge about 25 feet behind the boat until my crew parked the boat. Of course, it's easy to forget the harness lock is on when you are gybing, which leads to a "Keystone Cops" looking fumble on the trampoline...