Let's say I park my car on a busy city street. I leave all the doors open, the keys in, and the engine running. If somebody gets in and drives off, what do you think the police are going to say? "Yes sir, you were doing nothing wrong, and this is not your fault in any way!"
Let's not be ridiculous; most of the fault lies with the person who failed to secure their network. Just like locking your car, secuiring a WAP should be COMMON SENSE today.
Example: I live in the boondocks and my nearest neighbor is well outside the range of any WPA I set up, and I STILL use a rotating encryption on my network! I also lock my car in the garage at night.