Monday morning.
The office opens the diary and sees every instructor's day as a column, with pick-up postcodes on each lesson and a gap on Dan's afternoon.
A learner books online for automatic lessons in the east of town on Tuesday and Thursday evenings; the system offers only the two automatic instructors whose pick-up areas cover her postcode and who have evening slots, she picks one, buys a block of ten and the first two lessons go straight into his diary with travel time respected.
He gets the notification on his phone.