The Superman rounding off the pennies scam

Also featured in “Office Space”.

Has it ever been attempted in real life?

Short answer: yes.

I learned that this was the formal term for such schemes when reviewing a contract that stipulated that the software program I was hired to write must not contain any salamis.

I remember hearing the urban legend about this in the late 1960’s. Supposedly the programmer was caught when some little old lady asked the bank president where her fractions of a cent in interest were going.

A recent case involving credit card fees:
FTC Obtains Court Order Halting International Scheme Responsible For More Than $10 Million In Unauthorized Charges On Consumers’ Credit and Debit Cards (ftc.gov, 28 June 2010)

(italics mine, to emphasize the small amounts)