And yes, if someone did commit a crime using my network the police might visit, but what better defense is there than the fact that I have an open wireless network? If I enabled wireless security on my network and someone hacked it, I would have a far harder time proving my innocence.
He actually has a point there; it's one of the few viable defences I've seen tried in the multitude of file sharing cases that are going around :)

Oh, and my network is unsecured here, too. I'm not at all worried - after all, if I couldn't get a decent signal 10m from the AP and had to switch to wired to avoid that, anyone who can pick up the network from outside deserves access