How would you define an SEO malpractice standard? Is it performance based? If a site ranks and then looses this ranking, this could be out of the control of the SEO despite potentially having practiced good white hat SEO? Is the standard simply Google's TOS? Even if an SEO is guarenteeing rankings, this may not be malpractice in that while they can never be sure that the site will rank, the guarentee holds if they do in fact refund the money (but please note I do not advocate using a SEO who guarentees rankings, just exploring the point). If there is any hope it should relate to full disclosure between SEO and client. Google should not define it with thier TOS, but a client certainly needs to be aware of methods adopted, why they are adopted, the risks and potential rewards of the methods.
What? Like if I acidentally kill a website, or horifically disfigure it get banned from working on other sites? Like a sort of Dr of SEO? I'll have to get a second opinion on that.