"The best you can do is hold the owner of the internet connection responsible but this means effectively making people legally responsible if someone hacks their machine, hacks their wireless, breaks into their house. It is akin to charging someone with manslaughter should their car be stolen and used to run someone other. This is clear wrong, and not an acceptable path in a free society."

The owner of the internet connection is legally responsible -- Unless you are claiming that someone used your open wireless connection -- Which means that someone has trespassed on your network and is legally responsible for their actions -- whoever they might be.