Why do schools have lockers the size of a student?

[Fyraltari]

When I was in highschool we had lockers about the size of a backpack which made sense since it we only used them to store our backpacks during lunch break. Of course they were still big enough for the youngest of us to fit inside provided they folded themselves (hugging their knees and all). Then again, this was kind of a moot point since people apparently went around ripping the doors of the closets off their hinges.