When districtwide layoff notices hit every one of Detroit Public Schoolsâ 5,466 unionized employees late last week, an American Federation of Teachers spokeswoman called the move the largest âone fell swoopâ firing of teachers in union memory. More broadly troubling to teachers and education-reform observers, however, was DPS Emergency Financial Manager Robert Bobbâs concurrent announcement that he plans to unilaterally modify the Detroit Federation of Teachersâ collective bargaining agreement, the first test of a sweeping new state law. Public Act 4, signed by Michigan Gov.