On a long (about a hour) wild reach back to the beach in Puerto Rico, 2 meter swell, traveler almost all the way out, double trapped on a H16, I lost my concentation, capsized, turtled, and was held under the boat, by the shockcord wraped around my legs. I remained calm, but at some point wondered if I would ever figure out how to untangle myself.
A knife on my person or crew would of been helpful, I now carry a knife.
A quick release for the harness would have been ineffective as the problem was the bungee cord around my legs (unhooking was a no brainer).
A quick release of the shock cord in my case would have been more effective.