The same issue with respect to macros applies, however you can intercept the filesave and filesaveas functions in the document, by adding the following code to the document and save it from the vba editor (because you won't be able to save it from the document itself) as a macro enabled document.
It is not possible to determine whether a check box should be checked or not, nor is it possible to check that the selection in a dropdown form field is correct (unless you have default text which is not a valid result).
Code:
Option Explicit
Sub FileSaveAs()
On Error Resume Next
If DataCheck = True Then GoTo lbl_Exit
Dialogs(wdDialogFileSaveAs).Show
lbl_Exit:
Exit Sub
End Sub
Sub FileSave()
On Error Resume Next
If DataCheck = True Then GoTo lbl_Exit
ActiveDocument.Save
lbl_Exit:
Exit Sub
End Sub
Private Function DataCheck() As Boolean
Dim oFF As FormField
For Each oFF In ActiveDocument.FormFields
If oFF.Type = wdFieldFormTextInput Then
If oFF.Result = "" Then
DataCheck = True
MsgBox "You must complete then form before you can save it!"
oFF.Select
Exit For
End If
End If
Next oFF
lbl_Exit:
Exit Function
End Function