What do you think about me telling an unprepared kid to screw off on the day of the exam?
How would you tell an unprepared kid to screw off on exam day?
I'm not going to tell them that, I'm just going to leave them hanging
Even though a student is expected to be prepared for an exam, it's rude to tell off a student for failing to prepare for an exam. If you notice a student struggling academically, you should try to get that student help or at least point him to a resource where he can get help. Academics are important and falling behind can lead to a lot of negative outcomes in the future for those who aren't academically successful.
People fall behind for a reason, I'm only telling them to bring their act together.
It's best to try to be helpful to other students that are struggling instead of being rude. You should consider how you would feel if you were in their shoes.