Another way might be to just stop the save.
This goes behind the ThisWorkbook module in the VBE:
Option Explicit
Private Sub Workbook_BeforeSave(ByVal SaveAsUI As Boolean, Cancel As Boolean)
MsgBox "No saving"
Cancel = True
End Sub
But if the user disables macros or just disables event handling, then they could
save.
You could have the same trouble with any kind of save prohibition, though.
(It won't stop the determined!)