On the A2 near Vianen you break down on the hard shoulder at dusk. The hazard lights are already blinking and your car is clearly visible. The warning triangle is in the boot. What do you do with it?
Place it: without a triangle you are committing an offence here, even with hazard lights
Place it: it is not required, but traffic behind you will notice you sooner
Leave it: the blinking hazard lights already warn enough
Explanation
False — you think the triangle is mandatory here. If your hazard lights are blinking and your car is clearly visible, it is not mandatory, but it is wise; place it about 30 metres behind the car (Book p.169).