reply to Trencher
Re: Courts Actually, yes. In a case where you lend your car to someone, even if they have appropriate insurance (as does your vehicle), an accident victim could go after the vehicle owner and his assets. It's not criminal, but they could claim negligence and given good lawyering, they would win.
At a gun range people sign waivers, but basically an owner of an item could be found negligent even if he did not commit the crime. With HSI, there is a contract between the user and the ISP that you will not hold them liable for any of your actions (there may be Safe Harbor laws and so forth, I don't know the details). There are no contracts between your open hotspot and anonymous users, and it's likely to be a violation of your contract to willfully allow others to use your connection. Best defense would be ignorance, I would think.