ijimmy:
I don't have problems with my arrow falling of my rest. I was wondering why, these days, so many shooters do.
CBM SC:
Sorry! I missed your first question. If you are still referring to the "moleskin;" No, I do not use "moleskin." The material crowds the window. I do use a piece of thin suede to cover the access slot where the nuts to the rest is located. I cover the area to keep moisture and debris from getting in. The shelf is covered because it looks nice to match the area rather than having a "chopped" piece appearance.
Why do you ask? If you are thinking that I may have the window (side) area covered to dull the "plink" of an arrow
falling off my rest, 
there is no room for my shaft to do so. The shaft cannot roll off the window side of my prongs because I do not cant my bow and I do not shoot those carbon toothpicks.

If my shaft was to fall left, the shaft would fall off away from the shelf. Since I rarely have a problem with my shaft rolling off my rest, I do not need to wrap my window in thick sound deadening material.
As for keeping my arrow stable on the rest until I shoot, I use a small 65-cent homemade system that allows me to hold the bow upside down if I was to shoot while hanging by my feet.

The holder falls away within 2" of draw.