retrolefty:
The laser module may indeed be utilizing the built=in internal resistance value of the LR44 batteries to keep the laser from drawing excessive current and burning up.
That's a thought, I hadn't considered that. I don't know what the internal resistance is, but What is a lr44 battery current rating? - Answers suggests around 20 Ohms. If it's powered off button cells, is it safe to assume that the current consumption must be very low, else the battery would flatten unreasonably quickly? I suppose the battery capacity is only around 100mAh, so it would be possible to guestimate the current draw if the battery life was known.