I own a small business IT consulting firm, and on the web site we have our ToS listed. In our ToS is the following line:
[Business Name], or anyone working at the request of [Business Name], may not be held responsible for errors and omissions. This includes but is not limited to security lapses, data loss, and all general service interruptions.
Is there a prayer in heck of this actually having any affect in real life? And no, the client doesn't sign anything, this is just in our ToS on our web site.
(I am planning to get a lawyer to write up a real, and official "contract" customers have to sign, but I don't have the money for that right now.)
ETA: And no, I have no liability insurance yet, and I operate as a sole proprietor... But hey, what's life without a little risk?
ETA: I always forget to mention my location: Austin, TX, USA.