When processing a credit card, the charge will not go through if the credit card number is wrong. However, if the credit card number is right but the amount is wrong, it will process. It is VERY easy to input the amount incorrectly. The zeroes that are already in place remain as you key in numbers. So a gift of $150 could very easily be entered as $1,500. When you hit "process transaction," the message that comes up is "Please confirm you desire to process credit/debit card number XXXXXXXXXX." A simple addition at the end of this message that reads "in the amount of $150.00" would save the unfortunate event of processing a donor's credit card for $1,500 instead of $150. In order to double check the amount now, you have to back out of the processing, check the amount, and then do the process request again. I have finally gotten in the habit of double checking before hitting the process button, but it is all fraught with possible error at the donor's expense.