4.23 Printer Safes - Printer Safes must have a keypad with in a close range of the door and players must be able to see through the door to know there is printers in it or not.
Your door wasn't transparent. Valid warn, don't see a problem with it.

4.23 Printer Safes - Printer Safes must have a keypad with in a close range of the door and players must be able to [b]see through the door[/b] to know there is printers in it or not. Your door wasn't transparent. Valid warn, don't see a problem with it.