This would not be the craziest thing coming out of Greece recently. Government bonds dropped to junk status and austerity measures pissed off a lot of people. It's quite possible that students could be protesting teachers not being paid or being asked to stay home, and it wouldn't be the first time it happened either. I haven't heard anything about this in the news recently, it was mostly focused in mid to late summer, but I'm just saying that this sort of thing really isn't that unreasonable.