I'm not sure as to the reasoning behind it, but without running foul on the forum rules on not bashing encryption it is important to note that all of the encrypted dispatch channels in the Boston area are campuses rather than municipalities. Northeastern, Harvard, and Boston College are all encrypted whereas the only encrypted municipal/state police channels are tac channels. They also have a much, much higher proportion of digital frequencies in the campus field when compared with municipal police in the area. In addition to the aforementioned campuses, Bentley, Suffolk, Tufts, and BU are P25 while Simmons is NXDN and Berklee College of Music is DMR. In comparison, of the roughly 50 or so municipal/state police agencies in the Boston area that I monitor regularly, the only digital users that come to mind are Massport (on the Massport P25 system), Waltham, Burlington, Cambridge (on their P25 system), and Reading.