Or maybe it is because they don't want to play games where the Germans roll over everybody. There were some minor reverses and near run German victories in the early days, but the perception is of an unbroken string of German wins. It's a shame because pitting a company of Panzer IIs against a company of French S35s or a company of Panzer Is against a battery of Polish anti-tank is going to produce a challenge for the German commander.