Demonstrate to users- insecure APs

[WALI <hkhasgiwale () gmail com>]

Suppose I leave my Access Point in Unsecured Mode, no WEP/WPA etc.

Someone connects to my AP and receives an IP assignment via it's DHCP.

Is it possible to sniff all the traffic from all the machines that get's 
connected and browse the Internet/LAN through this AP?

I mean, apart from the usual money saving aspect of having a free ride on 
other people's money, ( at home) what else is the risk?