The federal Fair Housing Act (FHA) and its various state law counterparts are clear — a resident or applicant cannot be discriminated against because he or she filed a previous housing discrimination case or otherwise assisted someone in exercising their fair housing rights under the law.  Professional apartment property owners and managers know the law, but we are still required to ensure our community rules and policies are followed.
However, the situation just recently brought to my attention involves a resident who filed two previous fair housing complaints.  Neither had merit.  Management settled the first in an effort to show good faith with the hope that litigation with the resident would end.  When the second complaint was filed, we appropriately defended it.  And the agency correctly found No Probable Cause and dismissed the action.  As the resident continued to engage in conduct which management believed was a direct threat to the safety of our leasing office staff members, management issued a non-renewal notice.
You can guess what happened next.  A third complaint — this time for retaliation.  Rest assured, management did not retaliate against this resident.  But we are being forced to again prove our innocence.  Yet further evidence why management must keep good records and document what we do and why.  My usual recommendation is certainly that management must enforce its rules across the board.  I do not think it appropriate to essentially reward a resident who refuses to comport his or her conduct to what is required of all residents. 
But if we cannot document the reasons behind our actions, it can look like retaliation.  Even when it is not.
Just a thought.