One time, but thankfully only once, we took off in the van and then took the head count. Found we had left 2 of our 9 back at the house.
Conclusion: do the headcount before you pull out.
My 2 aunts had 4 kids ea and my mom had me so almost everywhere we went we had 9 kids. One of my younger cousins was quiet and a loner. He’d sit in the back of the house all alone for hours playing with his small cars. I can remember we left him on a couple of occasions. When we’d run back to pick him up he’d still be in the same place still playing. Those were different times. Lol