Tamper-resistant switch assemblies (26, 162) are provided including a first movement-sensing switch (28) and a second tamper-sensing switch
assembly (30), the latter including a switchable component (32) and an actuating component (34). Preferably, the switch (28) and switch
assembly (30) are housed within an encapsulated switch module (70, 114, 164), with the actuating component (34, 118, 138, 166) positioned above or to the side of the module (70, 114, 164). Mounting structure (36) serves to support the module (70, 114, 164) within a mounting opening (90, 112, 148) and is operable to prevent removal of the switchable component (32) and actuating component (34, 118, 138, 166) without significant relative shifting movement between the switchable component (32) and actuating component (34, 118, 138, 166). Any attempted tampering results in such relative shifting movement, thereby triggering an alarm.In another aspect, the invention provides switch apparatus (182) including a magnetic ball switch (32) with a first biasing magnetic component (194) and a second operating
magnet component (196). Adjustment structure (190, 192) permits selective adjustment of the position of magnetic component (194) in order to permit tuning of the apparatus (182) so as to prevent defeat thereof by means of a defeat
magnet (198) positioned between the
magnet components (194, 196).