The worst moment for a JVT battery is 7.30 on a school morning. The car was started cold, driven four minutes with every fan and light on, then switched off at the gate while a child is walked in. The restart asks for full cranking current from a battery that has had no time to recover. A weak one gives up right there, in the drop-off lane.
If that happens, put the hazard lights on and message us with the school name. A jump start gets the car out of the lane, and the technician then tests the battery somewhere quieter. Many parents book the test for the afternoon instead, at home, once they have noticed the first slow crank.