Open House "Looky-Loos"

I recently held an open house (sellers idea) on a beautiful Sunday afternoon. I had three couples come through, all "looky-loos"! These couples are career open house visitors. We see them every Sunday making the rounds. They usually criticize the home. They will nit-pick every little thing about the home, including the price, and then thank you for allowing them to visit. It is getting to the point where I will not encourage an open house for my sellers and explain that there are better ways to market the home. It is hard to convince some that there is a better way, especially if they visited several open houses before they bought their home. I explain to them that the majority of open house visitors do not buy the homes they are visiting but are simply comparing floor plans, price and neighborhoods. I also explain that there are a lot of "looky-loos" out there.