Anyone who doesn't pay their student loan in a timely manner. As the saying goes, if you want to find someone, put the student loan folks after em.
[On a realistic note, I understand some countries will check the status of such loans upon return (i.e. immigrations), and they make people sign a promise to re-pay]....
Otherwise, it's typically if you forgot to mark your ballot correctly in a blue state...
<sarcasm>
SDF_Traveler