Seating plans in general are a great school discipline idea because they clearly establish your status as the person in control of the room. This is because pupils quite literally have to follow your instructions as to where to sit. They can also be seen as a physical manifestation of the positive learning frame that you are creating for your class. Allowing the cultural architects of your class to choose to sit together, could encourage them to work together to create a negative frame that could well hi-jack your own. Sitting them next to others will dilute any negative influence that they may have on others, by placing them next to students who may be more receptive to your learning frame.