Which of the following is NOT a requirement for using a stepladder?

Standing on the top platform of a stepladder is not a safe practice and is therefore considered a requirement that should not be met. The top platform is designed to provide stability and a safe spot for the user to transition between levels, but it is not meant to be stood upon during a task. Doing so significantly increases the risk of falls and potential injuries due to the higher center of gravity.

On the other hand, the other requirements mentioned support safe usage of stepladders. Standing no higher than the second rung from the top ensures that the user maintains balance and stability. Using the ladder in a fully spread position prevents it from tipping over, and not substituting it for a straight ladder helps to ensure that the user is using the appropriate equipment for the task, further minimizing risk.