I'll do you one better, car headlights should never be off while the motor is running. Just like motorcycles since the 70s (maybe 80s?).
No switch at all, ignition on, headlights on, period.
No switch at all, ignition on, headlights on, period.
Parents who sit in their idling cars for (fucking) ages while their cars are facing the tennis courts thus blinding the player on the other side of the court for however long it takes them to either turn their car off, drive off, or someone to tell them turn their fucking headlights off.
I'd still prefer to override both on/off though.
Before that I've not had to intervene at all, as far as I can remember.
There aren't that many courts where cars park facing them, but my home courts are one of them ;)
When the oncoming cars do not have headlights on I find it easier to give them just enough attention to see that they are behaving normally leaving more attention to devote to things other than oncoming cars.
Especially the cars with the projectors that bounce around.