DataPaths created using the designer interface run every time you "Finish" a form. Sometimes a datapath may not be desired. 

What you can do in this case is leverage the BeforeDataPathRun event in the .NET Script Editor. 

The following example code will restrict a DataPath named "PDF" from running if a field named "Name" has a value of "NO PDF". 

<MiCode(FormScriptEventType.BeforeDataPathRun)> _ 
Public Sub Form_BeforeDataPathRun(ByVal e As BeforeDataPathRunEventArgs)
  If e.DataPath.Name = "PDF" Then
   ' make some kind of logic check to determine if the DataPath should continue
   If _Name.Value = "NO PDF" Then
    e.Cancel = True
   End If
  End If
End Sub