Abstract: The disclosure teaches a two component system for ensuring persons (such as infants), objects or animals are not unintentionally left unattended in parked cars. The system requires the driver (custodian) to activate a first component that emits a radio signal. The radio signal is received by a second component. The second component may be attached to the custodian's ignition key chain. The radio signal has limited range. If the custodian walks away from the car or first transmitting component without first disabling the first component, an alarm will illuminate or sound. The system may also be used with other devices such as shopping carts. It may also be used to monitor movement of disabled individuals.