For instance, at the end of the term students may ask why a teacher gave them a particular grade. Some may beg and plead that you change it. Some may give you a great excuse for their poor grades. Some may have their parents call you on their behalf.
You may even have a supervisor try to push you to change a grade for a sports star or to help school passing rates.
I think the best way to handle grades is to consider yourself the scorekeeper. Keep track of the grades and report them at the end. Case closed.