My understanding is that some dinghy (and keelboat classes for droop hiking) had the crew wired into the boat for fast tacks (you could change sides on an endless trap wire). Obviously a hook and ring would be a big improvement on that type of system. The new rule doesn't say "allows the sailor to self-disconnect from his harness while underwater for objects that have snagged his trapeeze harness by accident". Unless you are tied in to the trap wire, this is not enforceable.