I don't believe there has yet, but I read some where that it is technically illegal in UK if your site restrict access to anyone with a disability.
It scared this company enough, after one complaint that they paid upwards of 40k GBP to make it as complient, I suppose, if found guilty a site could be shut down and if this site is turning over millions then it is not worth the risk.
My thoughts, following the rules, you end up disappearing up your own :banned:
There is a lot of grey areas and its a bit of a laugh when the critiques own sites have mistakes.
In the end, making a site xhtml and seo complient, then your about 80% there.