Y'know, I've heard intelligent people make the argument that the imposed amendments to the Constitution are not valid (they were not properly ratified because Southern States were forced at gunpoint to "ratify" them in order to get the army of occupation out of their States). However, I must admit that it is in the jails/prisons that I have seen this raised to an art form. Fringed flags, Esquire as a title of nobility, sovereign citizen, misspelled name on the indictment - you name it, some prisoner has latched onto it (see here).
I'm not terribly surprised that Black prisoners have latched onto this sort of argument despite the fact that it has roots in White separationist-supremacy movements (click through and read the article as well). The guys in prison who are making these arguments don't care where the argument comes from. They want (1) an argument which will invalidate the prosecutor's evidence, (2) cause as much trouble as possible for the prosecution (either on the theory the prosecutor will give up and settle for a lesser conviction or just to be ornery), or (3) to entertain themselves.
When I was doing defense I ran into Black defendants who wanted to use some of these arguments. I can remember back about 2000 reading (and rereading) all sorts of statutes in the UCC section of the Virginia Code because one of my clients swore it would stop a child support case dead in its tracks. Unfortunately for the defendant, I couldn't find any of the stuff he kept swearing to me was there if I just looked in the right section.