I'm not a regular golfer either, but I would think that as long as you don't follow the example of many Xmarks members and pack your sporran with everything but the kitchen sink that the light weight of a sporran would not be an issue when golfing. The more stuff in a sporran the heavier it is and the heavier it is the more it impedes. I would also think a heavy sporran would hurt more when it swings up, as it will come back down.

Besides do you really need a cell phone, blackberry, keys, wallet, iPod, smokes, lighter, flask, glasses, book, road map, tire iron, Swiss army knife, broadsword, towel, stapler, etc,etc all at the same time? I only carry what I would in the pockets of my jeans.