Wireless network thieves

[Headless Thompson Gunner]

MAC address filtering will keep out most people.

Yep.  

There are lots of people in the world savvy enough to circumvent MAC filtering, but the odds of any of them living within 50 feet of your house are small enough.

[InfidelSerf]

Seriously, how could an ISP think it's a good idea to have the default settings for wireless to be A) on, and B) unprotected?

There is a very specific reason why routers from both ISPs and manufacturers come with wireless on and unprotected.
They don't want people buying the things plugging them in and immediately calling their expensive call centers asking stupid questions about why the thing doesn't work.
They want the average consumer to be able to plug it in and for it to work.
It's up to you to lock the door.

[mtnbkr]

There is a very specific reason why routers from both ISPs and manufacturers come with wireless on and unprotected.
They don't want people buying the things plugging them in and immediately calling their expensive call centers asking stupid questions about why the thing doesn't work.
They want the average consumer to be able to plug it in and for it to work.
It's up to you to lock the door.

Yup.  Just like when you buy a car, they don't lock the doors for you, but they give you doors with locks and a set of keys.  Plus, with all of the various systems that support one type of encryption or another, it's just easier to leave it open and let the user configure it for their specific environment.

Chris