There is a third category among the silencers. Those who have very good knowledge of the subject being discussed but do not feel confident enough to open their mouth. They need some kind of training before they come for GD.
Missing from this list of 6 is the candidate who starts abusing or gets violent!
In one GD I participated in, a candidate of Marathi persuasion lost his cool because he was having trouble composing grammatically correct sentences in English!
After a few tries, he erupted like a volcano and started cursing and threatening the other candidates!
The coordinator immediately called for help!
The situation got so bad that the police had to be summoned. This agitated candidate was subdued by the police and was put in restraints before he was taken into their custody!
A petite female candidate fainted and was rushed to the hospital!
The moral of this incident is be calm when you make your statements!
These days, it is difficult to say who your words might set off and how badly they may react!