Determined to stop the next Mandalay Bay bloodbath, Las Vegas resorts have begun experimenting with a high-tech device that gives each guest a "stealth pat down" electronically without patrons even knowing it.

Called Patscan Cognitive Microwave Radar, the new system is already being tested at Westgate Las Vegas Resort and Casino. Among the concealed hardware confiscated so far: Several folding knives, a machete, and a 9mm pistol.