Marty List brings us CYT freeware, which allows you to change the default user name that is shown at the logon prompt. This is useful when you have logged onto a user's computer and don't want them to lock out your account by typing their password with your UserName.

The readme contains:

Cover Your Tracks version 2.50                              A default user logon utility for Windows.  Allows you to change                               the default user ID shown at the next logon.                              Use Cyt.exe /? to view the optional command-line syntax.                              Copyright ©1998-2000 Marty List                              Requires MSVBVM50.DLL version 05.00.4319 or later.  To obtain the                              latest versions of the Microsoft Visual Basic run-time files, see                              the Microsoft Support Knowledge Base article Q180071:                                                  ==================================================================                              Revision History:                              2.50 	11/28/2000                              Added code to reset the user name shown for each RAS profile on Win9x.                              2.02 	07/20/2000                              Fixed a bug with DontDisplayLastUser on Windows 2000.                              2.00	06/19/2000                              Added support for Windows 2000 and Windows 9x.                              1.10	05/15/1998                              Added option to modify profiles and support for command-line switches.                              1.00	04/09/1998                              Initial release.