The black tape covers that part of the lens that is responsible for the swept-up part of a Euro-beam's lowbeam - the "/" in "__/". My guess is that these cars have Euro-beams that are used for driving on the right side of the road, and when you drive the car on the left side of the road, you have to cover that part of the beam so they will not blind oncoming drivers, who will now be on that upswept part of the beam. (did you notice if these cars were right-hand-drive or left-hand-drive? might they be foreign cars?)

The Euro-beam's parking lamp is a small bulb in the main reflector. The front turn-signal bulb holder has only 2 connectors, not 3 as in those used in North America. So when the parking lamp is on, you will see the main headlamps dimly lit and the side markers not turned on.