My teacher told us a story.
The British teachers are very chor-lor one. They see your paper
hor, the more it insults their intelligence, the angrier they get,
they can flip the paper so hard that the stapler can fly off and
then hor, they won't bother picking up your paper and then consider
marks gone. 
With string hor, at least no matter how hard they flip the pages,
your exam script won't fly off.
