A system for signaling that a person is in an vehicle is provided and includes a power source, a processing unit including a counter, a state monitoring unit configured to monitor an internal temperature of the vehicle and to monitor whether the vehicle is in an off state and a door monitoring unit configured to monitor whether any of the vehicle doors are open or closed, a first buckle receiver, including a first signal issuing unit, a first buckle to be removably inserted into the buckle receiver and to thereby cause the first signal issuing unit to issue an installation signal to the processing unit, a second buckle receiver, including a second signal issuing unit, a second buckle to be removably inserted into the second buckle receiver and to thereby cause the second signal issuing unit to issue an occupation signal to the processing unit, and an alarm unit.