Yep used to be horrible, but I got two of them Shooaways
http://www.shooawayusa.com/
they really work, I was amazed. But they must be in the sun light, don't do anything under the umbrella, the little reflector dots need the sun light to goof with the flies eye sight, but they really do work. Looks like the price has gone up some since I bought mine year before last , I got in on the two for the price of one deal $19.95, when they were newly out and trying to break into the market I guess, seems them Aussies know something about flies. Pretty safe around kids and animals, I have cats, they swat at it from time to time, great entertainment ..lol...but bottom line, flies stay away, a few will come by, but don't stay long, seems they really hate that thing.