easyday - I can only discuss first hand IPSC shooting. Sanctioned USPSA matches are run under a cold range. Magazines can be kept loaded, but not inserted in the gun. The gun is only loaded when the competitor comes to the line to shoot and is given the instruction to "load and make ready." The competitor unloads and shows clear under the direction of the range officer after completing the course of fire.
The only time a gun is kept hot is if there is more than one string during the course of fire. The gun usually remains "hot" between strings, but it is at the discretion of the range officer.
I would recommend all matches open to the public be held under a cold range. There has only been one death in a USPSA sanctioned match which was a freak accident. A young teen on the range that wasn't even competing or watching the match got hit by a ricochet in the head. The resulting lawsuit was a real mess for the range, shooting club, and their members.