A control system (16) for generating an alert, comprising, an input (102) including at least one sensor configured to provide person information indicative of a characteristic of a person； a processor (100) configured to receive information from the input corresponding to at least two of: an egress motivating condition determined at least by monitoring the change in output of the or each at least one sensor over a predetermined period of time； an egress prerequisite condition determined at least by monitoring the input, and corresponding to at least one of: a physiological characteristic of the person supported on a person support structure (12,14)； a characteristic of a person with respect to the person support structure (12,14)； a status of a therapy； and a status of the person support structure (12,14)； and an egress preparation sequence determined at least by monitoring information sensed by the or each at least one sensor； a memory unit including instructions that, when acted upon by the processor, cause the processor to determine, based on the information received from the input, when the person will likely egress from the person support structure and, if the person will likely egress from the person support structure, generate an alert.
