While MAC address filtering is easily defeated by smart wireless users, but it does protect your network from the uninitiated.

For example, other family members have the encryption key to your network and can give it to their buddies to use when they come over to game or whatever. However, they still can’t get on the network due to inability to add their buddies’ MAC address to the wireless router.

So it’s not totally useless.

I don’t see anything terribly wrong with running an open network if you have your own traffic VLAN’ed off or on a separate network entirely. Then you’re doing, as Bruce says, a “public service”.

But if you’re keeping your own devices on an unencrypted, wide open network, you’re not really protecting your own assets. That defeats the purpose of running a home network, in my opinion.

The other interesting argument for running it open is the idea of this leaving you open to repudiation – you could download illegal content and then claim that it was someone else using your open network. I know that someone has tried that defense in court but I am not sure of the legal outcome to it. Seems like an inefficient way to cover your legal ass.