The date and time was 5/21/2008 8:59 AM, and on a whim, Lanwench [MVP -
Exchange] pounded out on the keyboard:

I did explain what happens. I configure one printer. A user plugs in an
identical printer (just not the one I used). Windows detects it as new
hardware, installs another printer. Windows will then not print from the
one I had set as default.  I can't expect the users to go through the
process to reset the Windows default printer, open the Check-in program
and select a new printer every time another one is detected by Windows.
 There are over a dozen printers and a couple dozen laptops for this.

The date and time was 5/22/2008 12:09 AM, and on a whim, Uwe Sieber
pounded out on the keyboard:

This is the procedure used to allow multiple identical USB printers to
not trigger the "New Hardware Detected":

How To Stop USB Detection of Identical Printers

Used link below to learn how to disable detection, and then my steps to
locate the Vendor ID (Vid) & Product ID (Pid) values, and create a REG
file for importing into workstations.

http://www.uwe-sieber.de/usbtrouble_e.html#identical_drives as a reference:

1. First remove the printer from Printers and Faxes. This is required
because after the registry modification is done below, the printer needs
to be installed clean.  This will be the last time you will see New
Hardware Detected for this printer.
2. Open regedit
3. Navigate to HKLM\SYSTEM\ControlSet001\Control\DeviceClasses
4. Press Ctrl-F and enter ##?#USB#
5. When Find stops, expand the sub keys in succession until you see the
Device Parameters key below it.  If the printer you want is there, write
down the Vendor ID and Product ID numbers that are found located in the
prior selected key (that begins with ##?#USB#).  There should be four
digits after Vid_ and four after Pid_ . Those are the digits you enter
in creating the Binary value key: IgnoreHWSerNum11119999=01, where 1111
is the Vid and 9999 is the Pid, as used in the example on the web page.
(Note: you may find multiple listings of the same printer. The Vid & Pid
should all be the same.)

If the printer name in Device Parameters is not the one, press F3. This
will bring you to the next key.  Follow step 4 and use F3 each time
until the correct printer is located.

6. Per the web page, navigate to
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\UsbFlags
           and click on the key UsbFlags.
7. On the right side, right click and select New > Binary Value.  Type:
    IgnoreHWSerNum
and enter the four digits from the Vid first and then the Pid without
any spaces, and press Enter.
8. Double click on the new value and enter: 01 and press Enter.

If this will be used on multiple machines, right click on UsbFlags and
select Export. Name it something like UsbFlags and click Save (no
extension needed as REG is added).  Right click on the REG file and
select Edit.  I removed everything except three lines:

Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\UsbFlags]
"IgnoreHWSerNum04710302"=hex:01

The eight digits at the end of IgnoreHWSerNum will vary on every device,
so make sure yours is correct.  Save the file.

Now you can merge the REG file into any workstation using identical
printers, by copying the REG file to the workstation, right clicking on
the REG file and selecting Merge.  Answer Yes to add the information to
the registry.

Plug in the USB printer and Windows will detect the new hardware.
Swapping identical printers will no longer trigger the detection.

Thanks to Uwe Sieber for his web page and related information.