Thank you M'n'M! So the flag goes up ONLY when the skier is in the water? Good to know! My first thought was the flag was up whenever the boat was pulling a skier or the skier was in the water. I'll keep an eye out for it although since I don't pull skiers (Baja Outlaws don't make the best ski boats) and rarely have a tuber, I tend to not be in those areas that a skier or tuber might prefer but there's always a first time!! It doesn't hurt to be prepared!