I had this happen to me and I don't have inteen nor any school-oriented stuff in at the moment. I am using Insim and some of JMs hacks (the critical to me ones
and that's all as it's supposed to be a challenge neighborhood (see my idea of playing without hacks).
Anyway, the couple had 6 kids, 8 sims on the lot. When the last one was a child, all the rest teens, it also turned out that the founder had the same work schedule. So there were lots of 'leaving'/'coming home' messages. The child came walking across the back desert of the lot when the teens came home. He did NOT get off the bus (and he didn't have his homework - that I could find.) I think maybe the lot/game got overloaded with them all at the same time.
For game play purposes, I decided he'd played hooky and gone fishin' in the fluorescent neon water out back (he'll probably die of it) and dropped his homework in to boot. That did seem punishment enough. Next day he came home when he was supposeda.