(I wasn't going to tell this story, since the business involved did their very best to resolve the problem, but I figured someone reading this might be able to learn from our mistake.)
A couple of weeks ago, we took our family to a local bowling alley. The boys have only been bowling once or twice in their lives, and Kaitlyn had never been. This place has a summer special going on, where on weekdays from 11-2 you can bowl for free, up to two games, and only pay for the price of renting shoes. We had so much fun, helping Kaitlyn push a ball down the lane and watching our boys choose which ball to use every time (so many colors! so many choices!). Sadly, I didn't break 100. (But hey, considering the fact that I only bowl approximately once every five years, I'm impressed that I didn't get any gutter balls.)
We took our shoes back to the counter when we were finished, and Christian used his credit card to pay the grand total of $15.78 (for five pairs of shoes - not bad for over two hours of bowling). They have a pizza place attached to the alley, so the credit card slip has a place for a tip, but since we didn't eat any food, Christian didn't include a tip. He signed at the bottom of the slip and we went home happy.
A few days later, I was paying Christian's credit card bill, when I happened to notice that the most recent transaction was for the bowling alley, but the amount was for $21.00 even. I was a bit confused, and wondered whether Christian had left a tip. When he came home that evening, I asked him about it, and he assured me that he had only signed the slip for the exact amount of $15.78. The next morning, he called and spoke to the manager, who assured him it must have been some kind of mistake, and that she would be happy to mail us a $20 gift card to rectify the mistake. (In addition to crediting our credit card $6.00.) Apparently, after she got off the phone with Christian, she did a little research and found out that our credit card slip had the extra $5.22 added to it after we left the establishment. She called Christian back, apologizing profusely, telling him that behavior like that is not tolerated there, and that she would be sending our family an extra-special fun pack. So, a few days ago we went back and bowled on the side of the alley with the nice couches for free, and we got two large pizzas with everything on them for free, and as much as we wanted to drink, and then they gave us each a $7.00 credit card/token thingy to play in the arcade. And yes, we tipped the woman who brought us our food - in cash.
So, lesson learned - if you are not going to pay a tip on your credit card slip, don't leave that line blank.