How to avoid CUPS disabling USB printer

[Marcelo]

In our system users often turn printer off to avoid non authorized printing.
When CUPS tries to print and finds the printer off, it disables the printer.
That happens with USB printers but not with parallel printers.
lpstat tells me:

   # lpstat -t
   scheduler is running
   system default destination: Lexmark
   device for Lexmark: USB:/dev/usb/lp0
   Lexmark accepting requests since Jan 01 00:00
   printer Lexmark disabled since Jan 01 00:00 -
           Unable to open USB device "usb:/dev/usb/lp0": No such device
   Lexmark-2108            walter         9521152   Sat 24 Jul 2004 15:06:06 BRT

To solve this problem I just enable the printer.

   # /usr/bin/enable Lexmark

Is there any way to configure CUPS *not to stop* the printer in case of error ? so we don't have to keep enabling it every time users forget printer off.

Thanks in advance for your help ..... Marcelo ...........