Should I ask a store to carry through with a policy when a cashier made a mistake?
Probably. Is it normal for people to stick to the store policy?
You don't believe in an eye for an eye ? I made a mistake recently at the shop and the manager wanted to punish me for it. But, I didn't bother with his nonsense, why can't he go by the book every time?
It is good to follow the rules and get what you deserve. People might think you are petty if you make a big deal about a little mistake.
I don't care what they think about me making a big deal out of things.
You can want people to make things right but if you do the cashier might get fired or punished. That wouldn't be want the cashier to be punished for such a simple mistake. Just let it go.