Our business partners son comes to the office after school and hangs out with his dad until it is time to head home, or for someone to pick him up for cub scouts etc...
If something happened to him it would be really easy for me to not know what day I last saw him, or if I was convinced I did know and LE questioning to convince me maybe it was the day before.
It is a frequent visit, I am not responsible for him, and my days somewhat blend together as far as routine. Actually as I think about it now I don't know what day I last saw him.