I am sure they thought he was sleeping in the trailer when they left. He probably travels in the trailer quite often. You can't do that in the U.S anymore, but as a kid in the 60's, my parents let us kids ride in the trailer on trips. In France, maybe you can still do that!

Missing in this article is how old the kid was and how many people
were travelling together.

When I was a kid we took a trip to NH with my parents. There was 6 of
us kids. We stopped a few times along the way and at one place, a
supermart gas station, we all got out to stretch. My brother, who was
about 7, went into the mart without any of us noticing. We travelled
about 50 miles before anyone realized he was missing. When we got
back we found him in the store chatting up employees without a care
in the world.

Anyway, my point is, you shouldn't be so fast to assume the parents
were on drugs or anything else. Things happen.

What kind of dumb asses drive 200 miles without noticing there kid is gone? I think the parents should get introuble. I am a mother of 4 and I know things get crazy sometimes but I would never do that and also let my kid sleep outside alone on a bench at a rest stop. Stupid Idiots!!!!!!!!!!

When I was 12 we took 2 cars to Oregon 2 states away from home. I was sick and laying in one car. When we got to the rest stop I went to get sick in the rest stop and came out to see both cars gone. I stayed put (had many ride offers) and my parents/sister came back about 1 hour later after stopping to eat 45 miles down the road and realizing I was not with them. If it was one car then something would seem a miss but 2 cars very easy to misplace a rider

How old was this kid?

Youre absolutely right. I live in Belgium and kids are supposed to ride in car seats but its not enforced. We see kids on the drivers lap, moving about in the car....lying in the back widow...whatever. I can probably say that they wanted to get right on the road in the morning to avoid the bad traffic we have in the summer and woke up and drove off. Simple as that. Yes they shouldve checked, but knowing how things work there, that's a fair explaination (not an excuse, an explaination)