I have moved my documents location by following the tutorial at Move Location of Documents Folder in Windows 10
Is there any serious security risk in moving the documents from their default location and if so, how can I reverse the above move procedure?
It will not protected by user account password but HDD can be encrypted if you like.
It will have NTFS protection if your network protected by firewall you don't need to worry.
It doesn't sound like you Moved your Documents folder correctly, if you did, the shortcut to the Documents folder under C:\Users\[UserName] would lead to the Documents folder on the Other Data drive, whatever drive letter that is, not a My Documents folder.
If you use a Password or Pin to access your computer, all drives, including the Data drive are protected by the same password. No drive on your computer is more vulnerable then the other. As stated, you can Encrypt the drive for more protection, but it's not really necessary.
Quote