Possible Clues:

• *Security device that may be silent
• One's triggered by a break-in
• One going off for an unauthorised visit
• House thief alert
• One may be set for a vacation
• What shocks unwelcome guest - food tipped over twin girls almost ending on him
• Device to warn of intruders
• Sound evidence of an unwelcome admission?
• Security device
• Neighbourhood watch noise pollution to stop thief?