You may Cut a shared workspace and Paste it anywhere into your folder hierarchy. This transfer of the workspace is not visible to the other members, while any transfer of objects inside the workspace is, of course.
There is a default position that BSCW uses to place a shared workspace which has not yet been assigned a position manually: the top level in your home folder. BSCW places a workspace, to which you have just been invited as a new member, in the top level of your home folder – irrespective of the positions that this workspace has in the individual folder hierarchies of the other members.
If, e.g. by inviting additional members, a folder B, which is contained in a workspace A, is turned into a shared workspace of its own (workspace B), the position of workspace B in the original workspace A remains unaffected for the members of workspace A. For the new members, workspace B appears in the top level of their home folders.