1. A system for monitoring a validator that assesses a token, the system including: an input device for receiving messages from a machine including a validator, the messages containing data indicative of validator events; and a processor for deriving timing information for the validator events from the messages and for comparing the data and timing information with predetermined criteria; wherein the input device is adapted to receive messages indicative of the following validator events: an assessment of a token resulting in acceptance; and an assessment of a token resulting in rejection; and wherein the processor is adapted to determine walk-away events by comparing the timing information with the predetermined criteria, wherein walk-away events are occasions when an assessment of a token resulting in rejection is followed by a period of greater than a predetermined threshold duration without an assessment resulting in rejection or an assessment resulting in acceptance, and wherein the processor is adapted to electronically store records of the determined walk away events, acceptances, and rejections and to electronically generate an alert in response to determination of a selected criterion based on at least one walk-away event.