When one of the four seats is empty, nobody sits there. I thought it was a rule, but apparently it's just habit.

• Ayu (Ayupan)It is a rule. I made it.
  MomoSis, you didn't say anything about it yesterday.
• MidoriBetter to leave the seat open. In case someone's coming back.
  MomoMidori sometimes says scary things in a pretty way.