Do you think restaurant have the right to ban children 6 and under from resturants?

I just read this article about a restaurant in Phili that is banning children under 6. In the poll taken on MSNBC only 4 percent of the people answering the poll thought it was unfair. The rest said it depended on the type of restaurant it was or that it was about time.
In the article the owner said they don’t have a problem with the children as much as a problem with patrons who give them problems when they are asked to quiet their children.
They understand that babies are a different issue but they don’t feel the enviroment is one that, one should bring a baby too.
The restaurant decided to go through with the ban after many complaints to them from patrons.
Do you think this is fair, or should something else be done?
Should other businesses ban children under 6?