Besides losing any code you may have written that you’ll never get back, those pending changes or locks will be stored on the server until someone does an “undo” or a workspace delete.
Here is the undo command:
tf undo /workspace:TheirWorkspace;DOMAIN\TheirUserAccount $/path/to/file
Here is the delete workspace command:
tf workspace /delete TheirWorkspace;DOMAIN\TheirUserAccount /s:http://TFSSERVER:8080
I nabbed these commands from this blog post on Richard Murillo’s blog.
more later – joel