The thing is that the UBA (University of Buenos Aires) is public, so anyone can enter their buildings. That, and the fact of having a distracted crowd, makes it

The thing is that the UBA (University of Buenos Aires) is public, so anyone can enter their buildings. That, and the fact of having a distracted crowd, makes it a tempting target to a pickpocket. It doesn't have to be a student. It could be anyone passing, entering, grabbing something, and leaving the place before anyone notices something strange.