Vegetable oil will freeze eventually, but will continue to repel water when frozen (that's the goal). It's chemical makeup is entirely different than water and therefore won't "stick" things together solid like frozen water does. The advantages of using it are that it is incredibly inexpensive, you've probably already got some at home, non-toxic and biodegrade (fish friendly). I'd say give it a try, if it works... Great. If it doesn't, then try something else. Trial and error is the best way to go.
