does anyone know about hanging water , in ziplock bags, from nails around a restaurant, to keep the flies out?

Question

I have seen a few restaurants around town with ziplock baggies full of water hanging from nails around the open windows and doors. they say it's to keep the flies out and they say it works. If it works WHY does it work?
Also some people put gallon jugs of water around the perimeter of their yard to keep dogs from peeing on their grass does that work? If so, WHY?

No added chemicals are in the water.
I have asked the people at the restarants befor they always insist it is JUST WATER

good thinking about calling mythbusters

Answer 1

I occasionally go to a restaurant that had the bags of water hanging from the top of the door. When I asked about it, the owner said that the flies saw the water and looked on it like a water fall, or at least dripping water. This kept them out. The door was open all day and I don't think I saw over 2 flies (total, not in one visit) in the restaurant. The restaurant is on the coast and not prone to flies which I think may be a more valid answer as to the lack of flies inside. Last time I was there, the water bags were gone and the door was shut. Still no flies.

But it makes a good story. Maybe Mythbusters would check it out?

Answer 2

I thought that old urban legend died out a couple of years back. One of our local (Texas) BBQ chains used to hang up ziplocs of water and claimed it did the job well. Seems to me that the new window screens that they installed were what did the job.

With the drought as bad as it is around here, a leaky ziploc would ATTRACT the (&^%^%$! things.

I've heard about the jugs of water trick for dog repellent, too. I tried it and my neighbor's dog hiked his leg on the jugs the same as if they were a rock or fencepost.

Answer 3

The water contains admixtures of certain compounds which disperse into the local atmosphere.