Measure each stage deck from the immediate floor level, and the distance from the stage edge to the nearest place a patron can be. The rule is at least 18 inches up and at least six feet back. A stage that has been changed - new flooring, a rail moved, a stage extended - has to be measured again before it is used.
Entertainers can be filed by a house number rather than a name. Apron does not need, and does not ask for, anyone's home address or ID.