If there is already a copy of the file in your working folder, SSAFE will not necessarily replace it.
Using the Get Latest Version command has four possible outcomes:
When the file you are retrieving is not already in your working folder, VSS simply gets the file.
When the file in your working folder is identical to the file you are retrieving, VSS does not retrieve or modify the file in any way.
When the file in your working folder is different from the VSS master copy, and your local copy is read-only, VSS replaces your local copy.
When the file in your working folder is not read-only, VSS assumes that you have the file checked out, and doesn't replace the file. You can change the way VSS behaves in this case with the Replace Writable option in the Local Files tab of the Options dialog box.