I have always raced spinnaker boats with a chicken line for the crew and would never consider sailing without....... And yes my crew agrees
We found that on our old Tornado and now F-18, if we stick the nose in with the chicken line on, we never swim and we have stuck the nose in, in some horendous seas and winds. If both crew stay at the back, the boat will slow dramaticaly, then slowly drive through and bow pops out. If in doupt, just check out what the top T boys favour.
As far as safety goes, without a chicken line you will more than likely face a swim with the danger of going around the front and being ran over or caught under the kite.
With a chicken line, if you do manage to capsize the line is likely to still break under your jolting body weight, hook could straighten and if it doesn't, you will just hang there until the hull lowers (starts to turtle) enough for you to release. Hardly a dangerous scenario.
PS - chicken line attaches to the trapeze ring / dog bone by way of a hook.