It is unlawful for any person to manage, conduct, carry on or own the business of operating a rebound-tumbling device center unless there is present at all times such center is in use a rebound-tumbling device supervisor. It is unlawful to employ any person under the age of 18 years as a rebound-tumbling device supervisor or for any such person to act as a rebound-tumbling device supervisor. (Ord. 310 § 4, 1960).