My sentiments exactly. Contacts are something people ask for so they can sue, but I have no intention of suing anybody. Keeping my word, and recording things with email is good enough for most people.
I guarantee to do a good job and that the client will be satisfied with the results or won't have to pay my bill. Each client has different needs, so the definition of "satisfied with the results" get's defined in a series of emails. If I set proper expectations, the client will be happy, and I will get paid. If I am careful to choose only clients who act in good faith, I will get paid. If I choose a bad client, then it's my fault if I don't get paid.