Just in the last month, I had to call a bank to reverse four erroneous "Account Maintenance Fees" across two different accounts. It appears that intentional billing errors is the new business model for our struggling economy. (For the record, although I am responsible for maintaining these accounts, I did not open the accounts at the bank in question. My personal account is at a credit union.)
One of my friends remarked, "I got only two. They must not really be trying yet."
Many years ago, back when the dot-com bubble appeared unpoppable, a different friend of mine happened to meet somebody who sheepishly admitted that one of his previous jobs was at a what-we-can-euphemistically-call "adult online entertainment" site, where he was responsible for developing algorithms to determine which customers could safely be double- or even triple-billed.