I would not consider a chicken line a "safety" item. It will help prevent some, perhaps a majority, of capsizes / pitchpoles. However, when you do go in and still are hooked in to the chicken line, your fall from grace can be a bit more trecherous. Looking up as I was sliding down a trampoline (boat going over on it's side after something went wrong - can't remember what) I saw David Mosley go for a flying leap off the transom of the boat only to be caught short by the chicken line leaving him landing head first into the sail. It wasn't perty.

Imagine a pitchpole where the boat endo's and you're restricted by the chicken line. I would rather be thrown clear personally. That being said, the chicken line is indespensable as an energy and near pitch pole saver while distance racing.