they can. seriously.
is because, take DnT as a example.
12 people taking the course DnT, and you dont come, keep absent.
then you score badly in your exam, your overall mark all affect
your friends (11 friends who took DnT as subject) by 10% causing
their grade to drop. is like one for all, all for one.
of course, teacher can ask you to drop the subject, but parents on
the another side must agree. then talk to the admin (VP or P). if
everything goes well, the amount of money will be refunded to you
(depending on what exam paper you drop).