what is Overspray technique

I was reading the current issue of Fine Scale Modeler magazine. In the reader gallary on page 38 there was a photo of a Panzer III Ausf L. In the notes on the model it stated that there was a base coat of gray, and then an OVERSPRAY WHITE. Is this a technique. To me overspray is appling to much paint on a part or section of a model, and you need to correct this mistake. If this is a technique, what is the procedure. Please clairify. Thanks to anyone reponding in advance.