You've got to wonder if he used the same password both times. If he did then it strikes me that the teachers and school that should be raked over the coals for not putting even the most basic safegards in place to protect all that confidential data on the laptop -especially after already being shown up about it.
"The teacher’s computer reportedly had sensitive encrypted information related to the Florida Comprehensive Assessment Test (FCAT)." -The other thing jumping to mind is that if the sensitive data was all properly encrypted, then even with intent, the student wouldn't have been able to view or tamper with it.
Edit: grammar; as->that