Sitting on the porch of a local restaurant tonight and saw a ziploc bag of water tacked onto the eve of the porch. I asked what this was for and was told that it was there to keep the flies away from patrons while they ate in the open air. No one could tell me how or why it worked, only the swore that it did. Anyone ever heard of this? What's the mechanism that keeps flies away? Or maybe my leg was really getting pulled?