SharePoint 2007 - Add Users and Groups User Interface

My client just approached me to tell me they were having problems adding users to their brand spanking new SharePoint 2007 extranet site.

I promptly pulled it up and asked the client to walk me thru the steps they used so that I could troubleshoot the problem.  We navigated to Site Settings, then to People and groups, then selected Add Users from the New menu, so far so good.  I asked what user they were trying to add.  They told me and I began to type it in in the standard DOMAIN\User format.  My client mentioned that I had the slash the wrong way.  I immediately spotted the problem.  For some reason, the label next to this textbox says Users/Groups (forward slash), and my client had entered the user in that format.

Good grief, what a horrendous name for a label for this particular textbox.  I wonder how this got past End User testing.