Examples for recommending alt omission needed for testing

Can anyone provide examples of where the recommendation to omit the alt
attribute would apply?

Please provide public URLs so that UA testing and user testing can be
conducted..

-- 
with regards

Steve Faulkner
Technical Director - TPG Europe
Director - Web Accessibility Tools Consortium

www.paciellogroup.com | www.wat-c.org
Web Accessibility Toolbar -
http://www.paciellogroup.com/resources/wat-ie-about.html