This is completely and utterly misguided. When riding on a wet surface, the wheel splashes some water to the side, regardless of whether a fender is there or not. Water that actually adheres to the wheel (via surface tension) does not fly outward. The centrifugal force of the spinning wheel obviously directs the water to the midline of the tire where it is flung directly off the tire from the midline of the wheel. The spray hits you and your bike. Thats why you get the stripe in the center of your back. When the front wheel is turned slightly to the left, the back spray from your front wheel is aimed right at your DT. With a fender, the spray hits the underside of the fender and it either drips back onto the tire and is flung again, or the surface tension holds it to the fender and it runs along the undersurface until it drips off the front or back. Watch your fenders carefully when you ride. Most of the water drips off the ends and only a tiny amount (if any) ever drips off the sides. What's worse, a few drops, or forcefully spraying your DT with road grime?