I'm going to be participating in a church yard sale this weekend, so I got some rolled change from my credit union.
The credit union's policy is to accept rolled coins if the account number of the depositor is written on them. They usually do a “length check” to judge whether the roll is full or not, and put it into their cash drawer as-is. When another customer (me) asks for a roll of coins, they grab one, cross out the number on the roll, and hand it to me.
Something told me that I should count the coins in the rolls. I usually don't unless it's a roll of dollar coins. But today I did.
One of the rolls of dimes was 20 cents short. Since I was still at the counter, I could get the 20 cents. If I had walked away and found out later, I'd be stuck with the short roll. (How would they know that I didn't take the coins out myself?) The original depositor would have “won,” and the bank would have “broken even” on the short roll, but I would have “lost” had I not cracked open the rolls and checked them.
So count your change at the teller's window!