Apparatus are provided for infusion devices and related systems and operating methods. An exemplary system includes a motor, a sensing arrangement coupled to the motor to provide output indicative of a detected characteristic of the motor when the sensing arrangement is enabled, and a module coupled to the sensing arrangement to periodically enable the sensing arrangement while the motor is idle and detect potential unintended motion of the motor based on the output from the sensing arrangement while periodically enabling the sensing arrangement. In some embodiments, the motor includes a rotor configured such that its rotation provides translational displacement of a plunger in a fluid reservoir, and the sensing arrangement includes one or more sensors configured to provide output indicative of a detected magnetic field of the rotor magnet.