A biometric monitoring device configured to be worn by a subject includes a physiological sensor configured to detect and/or measure physiological information from the subject, and a processor configured to analyze signals from the physiological sensor to detect a signature unique to the subject wearing the biometric monitoring device, and determine if the detected signature is a first signature associated with the biometric monitoring device being worn or a second signature associated with the biometric monitoring device not being worn. The first and second signatures are generated by the processor prompting the subject to indicate at prior times when the biometric monitoring device is being worn and is not being worn.
