PS - assuming .5% [1 of 200] of Paypals customers let a $4.80 charge go to avoid having to call, don't catch it, or don't realize its an error, and assuming this happens to that .5% once a year, we are talking $5.7M of additional revenue every year. Yes, they intentionally plan for your ignorance, negligence, and convenience in their favor. PPS - bankers are really OCD about numbers and accounts, often fretting over pennies. However, some banks will "not notice" extra payments. My wife and I routinely made duplicate payments when we were first starting the household, and the honest banks and businesses notified us, or at least applied it to a balance - but not all. Corruption and cheating knows no bounds.