I got this information from Fat Wallet Finance Forums about restaurant servers stealing their way to higher tips on credit card receipts. I actually know a person who got ripped off for $200.00. That person left a $2 tip but the dot did not show and so the server made sure it was a $200.00 tip! Be careful people!

Let try to explain this easily. here is an example:

That was easy…

The sure fire way to protect yourself is to keep all of your receipts and check them against your credit card statement. But how many people actually save them and then remember to check them?

There is another way called check sums. Basically you are checking the sum of several digits to make sure they equal a  number that you have predetermined. There are lots of systems but I will explain the one used over at FatWallets.

Step 1: Look over your receipt

Before you ever pay a bill look over the receipt. Over charges are actually a more common rip off than tip tampering.

Step 2: Calculate the appropriate tip

Lets use the numbers below. The bill was $47.16 and the service sucked so 10% is the tip. Figure out the tip.

Step 3: Apply a checksum

Notice that the tip can be changed easily to 14.71 and the 51.87 becomes a 61.87. That’s not good! Adjust the amount of the tip so that the numbers in the final total to the left of the decimal point add up to the right-most digit. In this case, the total has a “51″ to the left of the decimal point (A). 5 + 1 = 6, so the final digit should be six. Adjust the total to $51.86 or $51.96 (B) by adding nine or subtracting one from the tip (C).

Step 4: Check your credit card statements each month

While the receipt will help you ensure no fraud was enacted upon your dining bill, you only need the statement to verify the checksum. For this example, simply locate the dining transaction, add the numbers to the left of the decimal point, and confirm that they add up to the right-most digit. If they don’t, you’ve been scammed.

This technique is not foolproof. If the scummy server had added nine dollars to the total—making it $60.86—the checksum calculation would still come back okay. But because it’s harder to turn a “51″ into a “60″ than a “61,” it’s unlikely your server will do this unless they’re wise to this particular checksum technique.

Step 5: Deal with the theft

If you hit a checksum that fails, dig out your copy of the receipt to confirm it doesn’t match the total on your statement. Next, do three things:

1. Call your credit card issuer. It should be fairly simple to get a credit for the difference between your actual bill and what you were forced to pay due to this fraud.
2. Call the police. You were the victim of a crime, so you should report it, even if it’s just a few dollars. If the stealing server has multiple victims who report his or her behavior, the police will likely take action against the server and/or the restaurant. Hopefully a few thieving restaurant workers behind bars will set enough of an example to discourage similar actions in others.
3. Call the restaurant (optional). At this point, you’ve likely got your money back and given all the information you can to law enforcement. You can try calling the restaurant to report the theft, but it might not do much. In the best case, the manager will recognize the server’s name on your receipt and confirm he or she has been suspected of wrongdoing. Maybe you’ll even get a free meal out of it for your trouble. Worst case, the restaurant does nothing.