I'm currently using Internet Sharing from my Ethernet over Airport on my Macbook Pro, however I don't want my SSID broadcasted^†. There doesn't seem to be an option in Sharing/System Preferences to hide my ssid or prevent broadcasting. Any ideas?

^{† My parent's restaurant has a wifi router, but it's on the roof level where the cable was installed. The signal it gets is weak, but works for the macbook. Their iPhones and 802.11G based computers can't get the wifi connection, maybe 802.11N on the macbook gets better penetration. I figure they could use the airport sharing from the laptop. For a restaurant type setting I don't think having WPA or WPA2 is super important. There's nothing sensitive or insecure on the network, so I figure hiding the SSID would be good enough for their purposes. It's not even active 100% of the time.}