As open buildings, hotels are typically on guard for any signs of trouble. So it's no surprise that the downtown Hilton Americas\u2013Houston just upgraded its video-surveillance system, installing one based on 3VR Security's digital recorder platform for the sake of efficient retrieval of video footage for research.Biggest insider threat? Sys admin gone rogue|6 tips for guarding against rogue sys admins|How to keep employees from stealing intellectual property|Video surveillance deployed inside London public bathroomsHilton Americas-Houston's new networked digital-video system also includes facial recognition capability so Hilton can input a digital facial image that can send out an alert related to that individual if picked up by the video surveillance cameras."A homeless person was trying to sneak into the hotel, and we got a shot of him and put it in the system," explains John Alan \u00a0Moore, the hotel's director of security and life safety, by way of example. When the video system picked him up trying to enter the hotel again, the system sent off an alert, so security might escort him off the property.Security quiz: How well do you know the insider threat?But the hotel isn't just monitoring for potential outsider threat; it's also keeping an eye out for rogue insiders, too.The hotel is using facial recognition to monitor employee behavior, paying particular attention to any former employees who leave on less-than-pleasant terms. All employees are informed that video monitoring of them takes place.The video system monitors the areas where employees come to punch into time clocks in order to verify the person's identity. But perhaps more significantly, the facial recognition system is used to watch for any suspicious activities of employees or former employees."If someone leaves under bad conditions, we set up alerts for that," Moore says. If the former employee suddenly showed up at the hotel, the video surveillance system would send out an alert.In any serious cases related to any trouble, the video surveillance footage is stored and can be e-mailed to insurance carriers or the local district attorney. The system has 1TB each of storage and backup and only saves movement in clips.The video surveillance system is used far more often for examining more mundane problems, such as when a guest complains of misplacing an item or wondering where the valet is. And the hotel isn't doing facial recognition of its guests -- though it would be nice to know whenever a top celebrity might walk through the door.Read more about wide area network in Network World's Wide Area Network section.