in the eyes of the law if the broadband connection account is under your name, and someone, even if it's not you downloads copyrighted files, and gets busted you take the fall, unless you can honestly prove it wasn't you, like your Wi-fi was illegally accessed
in this case the owner has allowed others to share his internet connection, and thus takes the fall
imo it's not fair but thats what the law is on about, your supposed to be responsible for who uses your internet connection, and for what purpose