The reason why you can turn the parking lights on one side at a time is also legislative. Europeans are more likely to have to park in the street, and need to light their cars for visibility if the street's not lighted. IDK about now, but at least in Germany in the past it was illegal to leave your car on an unlighted street without parking lights, and if another driver hit your unlighted parked car the accident was your fault. What you'd think of as the normal parking light position, one click before the headlights, was considered city lights, as in large cities was illegal to use headlights at normal brightness; again, not sure about current laws.
'97 SL500, 40th anniversary edition
'04 Olds Bravada (SWMBO's)
'06 Lexus ES330
'89 560SL (sold)
SL--Anything else is just a Mercedes.
(Kudos to whoever said it first)