Thousands of foreigners are abusing Sweden’s student-visa system by entering the country as students but not attending classes, according to the site The Local, which cites a new report from the Swedish Migration Board. The report “suggests that up to one-third of students who are granted resident visas in Sweden do not show up for class,” says The Local.

Around 15,000 people are granted one-year residency permits as students each year in Sweden, but until this year, they faced few checks to make sure they were actually attending college. Previously, in addition to paying an application fee of around $1,000, all applicants needed was a letter of admission from a higher-education institution and proof that they had enough money to survive while they were in the country.

Beginning this autumn, students from outside the European Union, the European Economic Area, and Switzerland will be charged tuition at Swedish universities, which remain free to all others, and a new system will go into effect requiring institutions to report students who don’t show up for class to the migration board.