1. A method for reducing violent acts during an event held in a crowded venue, the venue including seating to accommodate spectators to an event, the venue further including at least one parking area to accommodate vehicles driven by spectators wishing to attend such event, the method comprising: providing at least one entry port for persons to enter into the crowded venue; forming a photographic image of each person who approaches the at least one entry port seeking entry into the crowded venue; comparing the photographic image of each person seeking entry into the crowded venue to facial images compiled in a first database of facial images of persons who are known to be violent to detect a likely match; alerting at least one law enforcement officer of a detection of a likely match between the photographic image of the person seeking entry into the crowded venue and a facial image of a person known to be violent; providing at least one vehicle entry port for vehicles to enter into the at least one parking area; providing a license plate reader at the at least one vehicle entry port for reading information appearing on a license plate associated with each vehicle seeking entry into the at least one parking area; comparing the license plate of each vehicle seeking entry into the parking area with license plates compiled in a second database of vehicles associated with persons who are known to be violent to detect a likely match; and alerting the at least one law enforcement officer of a detection of a likely match between the license plate of the vehicle seeking entry into the at least one parking area and a vehicle associated with a person known to be violent, wherein the comparing of the photographic image of each person seeking entry into the crowded venue includes transmitting the photographic image of each person seeking entry into the crowded venue to a third party and, in response, receiving an alert that the person seeking entry into the crowded venue is known to be violent if the likely match is detected between the photographic image of the person seeking entry into the crowded venue and the facial image of the person known to be violent, and wherein the first database is a third party database controlled by a first entity and the second database is a third party database controlled by a second entity.