I guess without knowing what time AB and her bf got busted at the school, the possibility exists that she didn't do much of anything that day. Coulda gotten to school, scoped out her bf for some doobage, and that was it. Really makes ya wonder if she spilled the beans to him while in an altered (and possibly paranoid) state! Maybe even planned a getaway, considering he was also skipping school. Did he have his own car that he drove to school?
I should clarify that I do believe that detail about getting high, simply because I can think of no other explanation for LE delaying her questioning until Friday when they initially sought her out on Thursday to be questioned!
If they did indeed get caught on school grounds smoking during class hours, I imagine the bf got in trouble himself with the school. Would have made for some interesting bargaining chips during his own questioning with LE.