Have a scale at the mat, depending on the tournament weigh in there. Some allow a 2 pound allowance after the first weigh in, some weigh in before every match, some have random weigh ins after the first weigh in. It prevents a kid from makig weight, gorging, and especially helps with the night before weigh ins. Usually the argument is not enough scales, some states that do this require the participating clubs to bring a certifed scale to eliminate this problem. Oters will have one or two scales at the head table, the wrestler reports to the head table before going matside.