Maybe they wanted to recruit students to join their crew? No, that didn't seen very likely, unless they kidnapped them, that would make more sense. Still, it was silly to think that pirate crews were made up of kidnapped magical students. Pirates want one thing and one thing alone, treasure, and schools were often known to harbor antiques that could cost millions of galleons. "Perhaps," Eino began with his hand raised "they were looking for something in the school? Something valuable?" They would be able to infiltrate the school, in spite of its magic protections, because they could also use magic. "Or maybe..." He continued after a brief pause, "they wanted to hide something in the schools." They did have all those magic shields and were well hidden from the Muggle world so it would be a safe place for them to secretly harbor all of their treasures in such places.