Can't remember seeing a motor with any pullup resistors, but I have seen some (generally much older motors) that had hall effect sensors that only worked with 5V.
Roar specifies 5V input for the sensor board, at least in the rule book. But the sensors on the boards can be either push pull or open collector, so the analyzers use pullups on the GPIO pins just incase they are open collectors on the sensor boards. Ultimately though, this means you should get a high 3.3V from the Tunalyzer on the sensor cables when not connected to a motor.