This week there have been two beatings of bus drivers by teen aged girls in Christchurch... then there was me using my PDA to chat to my Dad on Skype... Humm.... another no brainer.
Maybe I haven't had enough coffee yet, but I'm missing the link between bus-driver beatings and your VOIP call.
The mall has had this open AP for months now and it's been well advertised on a number of geek lists yet it's still open. I've had my APs open for months and I'm still waiting for the geeks to show up with their yargies and free beer... hummm another no brainer.
I don't think the general public are up to play with Wifi yet. As has been mentioned in other threads before, if you give unlimited free something to the public in NZ, it'll get abused eventually - e.g. the free texting thing.
How do you give away some data? Post a sign on the front fence? Make your SSID=FreeNode ? Do you tell other people it's NOT a free node by locking it down?
I think the whole open wifi thing is still too new for standards and the law to catch up. Have a look at this article on wifi eavesdropping, which mentions a case of a Florida man going to jail for eavesdropping. If the AP owner doesn't mind people using it and they've put security in place against malicious use, etc, I don't see a problem. But I do see that your ISP might mind, especially if you're on an unlimited plan. Dangerous communist ideas - it's digging into ISP revenue!!! :-)