Letting a stranger contact a car owner without giving them the number
There is a small, very common problem in Indian cities that turns out to be a surprisingly good systems design exercise.
A car is parked badly. It is blocking a gate, a driveway, another car. Someone needs the owner to move it, right now. The traditional fix is a phone number written on a sticker on the windscreen.
That works. It also means a stranger — any stranger, forever — has the owner's personal number.
Why the sticker is worse than it looks
