This is a grey area. Casino security are not metro police. Unlike government law enforcement, casino security are not bound by the Fourth Amendment's reasonable search and seizure restrictions and stop and frisk laws. Casinos often set up metal detectors outside special events such as concerts, sports matches, or carnivals. People who do not wish to be scanned can simply leave the event. Some Las Vegas casinos are also experimenting with microwave radar technology. Gun sensors are set up near entrances, and then casino staff can turn people away who show up on the radar.