We did the same thing to sneak in to drive ins.
Lol! I was thinking the witness could have given the Mother a chance to correct the situation first, before calling the Cops. The article doesn’t say she resisted getting the boy out of her trunk once it was noticed, or that she argued about it.
When I wasn't much older than 13, I had a buddy with a 1957 Plymouth Belvedere with an absolutely cavernous trunk (and no spare tire). We lived in a one-horse town and to entertain ourselves one Saturday night, we put six kids in the car and another six in the trunk and went driving around. No, I'm not kidding.
Every time the driver pulled up to a stoplight, he'd put the car in park and everybody in the car would jump out and run back to the trunk and open it. The six who had been in the trunk would get out and run around to get into the cab. And the six who had been in the cab would crowd into the trunk.
The objective was to complete the exchange before the light turned green. Then whoever was under the wheel would drive to the next traffic light and the whole operation would start again.
We called it "the Polish Fire Drill" (no offense intended to any Poles among us, ... unless they're demoncrats).