Red tail, Thanks. When you try the wrist idea, remember to let the wrist be relaxed. It will come to that position naturally. Don't "force" it.
DDave, I too have to resist trying to help when I see something like that. You are right, a competition is the last place to try to correct something. For years, I've seen the "open hand" bow grip and the catching/grabbing reaction of the bow hand. The bow hand is the ONLY part of the body that can affect the shot both before and after the release.
Many people think that they are relaxed with their fingers sticking straight out. Try this experiment. Totally relax the fingers of your bow hand (they will naturally curl inwards). Now grab your bow forearm with your other hand and straighten your fingers. Can you feel the increasing tension in the tendons of your forearm? That is what I mean when I say "don't use any muscle or tension that is NOT required for the shot. Every little bit of tension that is not required will lead to increased "shaky-ness" and loss of control.