I am quite confused with Mike’s explanation.
Leon will only attend if Sarah does not. This tells me that if Sarah does not attend, then Leon will attend. It doesn’t say anything about what happens if Sarah attends. Leon could still show up or he could just not attend. Uncertain.
Where do you get that Sarah attending guarantees that Leon will not attend? I am so confused with your explanation for these drills.
and no offense, me understanding is more important that “what top scorers think”