Yes! The two Lemo connectors are wired in such a way that the user can plug a secondary power source into the passthrough Lemo connector, so the primary power source can be unplugged without interrupting power to the device.
Since the BreakerBatt is designed to pass power through from one Lemo to the other, there is no protection against backfeeding power between the two. In this case, it is recommended only to hot-swap using identical voltage sources with diode protection to prevent backfeeding of power to your DC power supply. Never hot-swap with Lemo cables wired for opposite polarities.