It's apparently simple. Bus driver neglected to do his job. Doesn't require more than a 5 minute Q&A. 1. Was bus driver aware of policy of checking bus? If not, why not? 2. If aware, was something critically important happening to prevent driver from checking the bus? If so, what was it, and why didn't driver check after event was over? 3. If nothing occurred to prevent checking the bus, driver failed to follow SOP, therefore incurring some adverse action. Even Nifong couldn't screw this up.
There is just no excuse for this! I swear, my son is 8 years old, he had a field trip last week. I told him before he left, as I have been telling him since he was in daycare: DO NOT FALL ASLEEP ON THE BUS! I am scared to death he'd get left behind and panic. How hard is it to check the seats before you get off the bus??