SharePoint Designer Workflows (Declarative Workflows) and User Context
A wonderful post has been made a short time ago on the SharePoint Designer blog. This is something I highly recommend anyone who uses SharePoint Designer for workflows to read as it contains very important information. http://blogs.msdn.com/sharepointdesigner/archive/2008/09/28/declarative-workflows-and-user-context.aspx
“The basic thing to remember is that declarative workflows (the one’s created by SharePoint Designer) always run impersonating the user who started the workflow.”
This can help explain why many people run into permission ‘issues’ and trouble with these workflows and can help give you a better understanding of how the workflows work and how the system was designed (and updated).
Hope this helps someone and again I highly recommend reading this one over,