You don't have to be an IT expert to be able to make use of your neighbour's security enabled Wifi network. Just watch one of the dozens of online videos that explains how.
Despite most of them being fitted with some kind of password (WEP, WPA etc.), Wifi networks are still relatively vulnerable. And by using another person's network, hackers can illegally download documents or attack websites without being traced.
If pirates should download paedophilic pornography, it's the owner of the home network, the person who pays the monthly wireless fee, who will find himself in court. In France, an anti-piracy law called Hadopi 2 enforces this by making it impossible to sentence a home network owner for having a poorly protected network.
This video, viewed over a million times, shows how, with the aid of software, you can get hold of the password to a wireless network.