Colin
See the "More Info" part of the following reference. I think that explains why the 10 user limit is sometimes not a problem. From my observations the average office might have more than 10 "connected" but not 10 being active. But if you have Active users then the 10 user limit will bite.
http://support.microsoft.com/default.aspx?scid=kb%3Ben-us%3B314882

>Hi
>
>I understand that the number of concurrent Win2k Pro sessions is limited to 10.
>
>Has this been proven in practice?
>
>Is this a limit on the number of machines that can be logged in at any one time or the number that can access a specific app?
>
>Colin Northway