I agree with Robert here. I have been doing this for a very long time and I have never used a discalimer nor would I use the services of anyone who does. If you have no faith in your work why would I? If your auto mechanic did your brakes but added a disclaimer that said "I did my best but if you get killed because the brakes didn't work I won't take responsibility" would you use him or find someone else? If you do a good job and carry the proper insurance then I don't see the need for a disclaimer unless you know that you are not qualified to do the work. I believe disclaimers are for those who do not belong in this business.