I gave in to the urge for dutchware bling and added a tarp biner to my zipper cord - and went so far as to put an eye in the cord to put into the binder to get rid of the unreliable knot on my ridge line. Then I took it another step further and put an eye on the zipper end so the former larks head knot can't come loose.

(once you learn to do simple buried brummels and Macdonald brummels, you start wondering why you ever bothered with knots)