Possible Clues:

• Empty room population?
• 0% of the group
• Not any person
• 0% of the people
• Dismal turnout for a party
• Cipher as a small number, not two or more
• Cipher 12 ultimately unsolvable
• Not a single person at twelve has ecstasy
• "... tree falls in the forest and ___"
• To whom you might be instructed to tell a secret