My Legal Environment students are required to observe a trial court in session during the semester. I just finished reading the written expressions of their observations. Many are initially surprised to encounter metal detectors at the entrance - although upon reflection are understanding. Incidents like the ones depicted below are rare, but their ocurrence must be anticipated and guarded against. I wouldn't show these in class before the court observation assignment is done as they might be too scary. But shown afterwards, they illustrate the importance of courtroom security precautions.