Possible Clues:

• Absentee, as at the theater
• Food that is a source of discomfort! One keeps away
• Question boy over earlier absence
• Truant, e.g
• Small numbers -- in what way is that something bothering restaurant?
• Absent acceptee
• Absentee for an appointment
• Guest who fails to notify cancellation, of a reservation perhaps
• One won't turn up to eat without coming back
• Person who never arrives