It also occurs to me that there might be some misunderstanding about Unassigned Devices shares, and Unraid User Shares.
Unassigned Devices plugin lets you share, on the network, devices that are not part of Unraid cache or array. These will show up in Windows, for example, next to your Unraid User Shares. But they are not part of Unraid User Shares. If you move one of your user shares completely over to an Unassigned Device, it is no longer an Unraid User Share.