[zngtk4]

>what if one of his class mate had thrown away his homework notebook. Would he be still be able to sue the other kid? Courts aren't setup to deal with this kind of issues.

He actually would still be able to sue the other kid. However, his damages would likely be rather small, and thus he would go to small claims court, which is setup to deal with this kind of issue. Probably he could also make a criminal complaint against the other kid if he really wanted.