No more flies?

I copied this from another forum I participate in, any one want to try it and report back to us?

This was sent to me by my cousin. Thought it would be interesting to some. I am going to try it at the Shack!

We went with some out of town friends to Sweety Pies on Sunday for
breakfast, and we sat in the enclosed patio section beside the house. We
happened to notice a couple of zip lock baggies pinned to a post and a
wall. The bags were half filled with water, each contained 6 shiny new
pennies, and they were zipped shut. Naturally we were curious! Ms Sweety
told us that these baggies kept the flies away! So naturally we were
even more curious! We actually watched some flies come in the open
window, stand around on the window sill, and then fly out again. And
there were NO flies in the eating area at all! This morning I checked
this out on Google. Below are comments on this fly control idea. I'm
now a believer! More comments not included here were about pet dogs and
fly problems.

Zip-lock water bags of all things

Sue says:
Many people swear that a zip-lock bag filled half-way with water and
attached over entry-ways will repel flies. No one yet knows how or why
it works, but there is speculation that it has something to do with the
way the moving water refracts light.

Ann Says: I did try the ziplock bag and pennies this weekend. I have a
horse trailer with full LQ.
The flys were very bad this weekend while I was camping. I put the
baggie with pennies above the door of the LQ. NOT ONE FLY came in the
trailer. The horse trailer part had many. Not sure why it works but it
does!!!!!!!

Danielle Martin Says: Fill a ziplock bag with water and 5 or 6 pennies
and hang it in the problem area. In my case it was a particular window
in my home. It had a slight but significant passage way for insects.
Every since I have done that, it has kept flies and wasps away. Some
say, that wasps and flies mistake the bag for some sort of other insect
nest and are threatened by this.

Maggie Says: I swear by the plastic bag of water trick I have them on
side porch ( our house entry) and all around the basement door. We saw
these in Northeast Mo at an Amish grocery store & have used them since.
They say it works because a fly sees a reflection & won't come around.

Just DJ Says: Regarding the science behind zip log bags of water? My
research found that each of the millions of molecules of water presents
its own prism effect and given that flies have a lot of eyes, to them
it's like a zillion disco balls reflecting light, colors and movement in
a dizzying manner. When you figure that flies are basically prey for
many other bugs, animals, birds, etc., they simply won't take the risk
of being around that much perceived action. I moved to a rural area
ant thought these hillbillies" were just yanking my city boy chain but I
tried it, worked immediately! We went from hundreds of flies to seeing
the occasional one, but it don't hang around long.