I mentioned a few days back on another thread my understanding that "complaint procedures--and note, this is for individuals--should have been widely posted," and promised to find out details. I have heard back from my informant (I use the term in its neutral sense) that it is the university's own complaint policy that should be widely posted rather than that of SACS. Apparently there is no requirement that the SACS complaint policy be advertized. But it does exist, and is valued in the review process.
Once again I will refer you to http://www.sacscoc.org/pdf/complaintpolicy.pdf, which includes the language, "The Commission on Colleges recognizes the value of information provided by students, employees, and others in determining whether an institution's performance is consistent with the Commissions criteria for attaining or maintaining accreditation. The Commission's interest also is in insuring that member institutions maintain appropriate grievance procedures and standards of procedural fairness and that the procedures are applied appropriately and consistently." Note that the Complaint cannot be filed anonymously and cannot concern local issues best dealt with in house but certainly can deal with issues that compromise SACS accreditation.
Please also note that complaints may be filed by "students, faculty, and other members of the public."