WLANs are brilliant...
Here's what I think is an interesting story:
I take the train to work and it takes about 45 minutes. Quite often, I'll be using my laptop during my commute and I have a wireless LAN card in it. I also have a free program called NetStumbler that goes off and looks for available wireless networks. I use this when I'm at another location and want to see if there's an available WLAN I can camp out on (to enjoy free Internet access). Anyway, at the end of the train journey, NetStumbler had picked up around 50 WLANs, of which about half had no security enabled whatsoever, which means I could get access to the Internet through their network (assuming the train stayed in one place for long enough).