I am a Rug Doctor employee.  My office recently had a rental unit get rented and sold on Ebay to an unsuspecting buyer.  It is considered stolen.  The easiest way to tell is that most RED machines are rental units owned by franchisees.  BLUE units are typically for sale to the general public. 
 If a red unit is listed for sale, ask the seller to send you a photo of the serial number rivited to the top of the machine.  Serial numbers are also etched to concealed parts of the machine.  You can phone Rug Doctor at 1-800-784-3628 to verify whether the machine is legitimately owned, or is stolen from the company.  Not ALL red units are to be considered stolen, as some may be sold when deemed no longer suitable for rental service.  But you CANNOT get parts for these machines from Rug Doctor without providing a serial number.

The unsuspecting purchaser of this machine is losing the unit because it belongs to us.  The seller of it has caused the purchaser problems with the police, and possible financial stress.  Don't get duped, check out RED units before buying them!!