In the printenvironment I manage I had the complaint that from time to time a printer reprinted all the past jobs. After looking into this issue I noticed that the printqueue was building up rapidly to over 300 jobs in the queue all with the message 'sent to printer'. It turned out that the security group 'Creator Owner' with permission Manage Documents was missing on the printer that was having the issues. You can rapidly set permissions on printers with SetACL from Helge Klein.