“Such software can never fully test compliance with WCAG”
that’s partly my point though…what else is a web manager going to rely on if they can’t assess a webpage themselves? As the developer, you may have to justify yourself against auto test results that you know are flawed

“You shouldn’t have non-technical staff adding raw HTML content. That’s a sure way to guarantee your site’s eventual inaccessibility” I totally agree, and I’ve been advising our clients the same thing. But if the client demands an option to have free reign over their page layout then the client gets.

“I see scenarios arising where a web manager or sponsor will never sign off a project on the basis of some automated accessiblity testing software’s results.”

The petition suggests compliance with WCAG, not with some automated accessibility testing software. Such software can never fully test compliance with WCAG. For example, it cannot distinguish appropriate from inappropriate ALT attribute content.

“where you have a team of ‘non technical’ editorial staff adding content, it only takes a font tag here or there within that content to cause a page to fail AA.”

You shouldn’t have non-technical staff adding raw HTML content. That’s a sure way to guarantee your site’s eventual inaccessibility. You should you use some sort of transformation on the content they add to ensure it is valid and conforms to guidelines. Tag soup-based systems are intrinsically broken.

The focus of accessibility should be on the user, the petition should therefore focus on the user, and because it doesn’t, I don’t feel it is right to sign it.

Now if it was reworded I may well change my mind.