Bingo!
CaptainSandL, I think you've hit the nail on the head. The Captain on this CAL flight was a good friend of mine, and we've discussed this very thing. If you look at a short-body 737-500 with winglets, pay careful attention to how in a a direct crosswind the winglet actually partially obscures the vertical stabilizer, thereby reducing overall rudder effectiveness. Plus, if the crosswind limit was 33 knots, what would happen if there was a gust exceeding that limit?