These days, modern banking and technology is pretty good at nailing crooks. Basically, electronics allows a certain "ID" on transactions that are hard to fake or alter. There's a long history of bad guys trying to insert their evil ways into banks' systems that protect customer identities and assets.

Back in the 19th century, machines that embossed a check  with some identifier—numbers, a phrase, whatever—were used. The machine punched little holes through the check that formed "40 dollars," or "CANCELED," or whatever. A cashier need only hold the check up to the light and see the cancellation peeking through the many punched holes. It discouraged forgers from altering the written portion of a check, changing 40 to 400 or altering signatures.

But bad guys have been as cagey as good guys, history shows. (Fortunately, the score is still lopsided in favor of the good guys.) A forger named Carl Becker made a name for himself at the turn of the century and put together elaborate schemes for cashing other people's checks. He got hold of a check in 1895, already cashed for 12 bucks. (Becker had guys on the "inside.") He altered the "12" to "22,000" and did microscopic work on punching new holes in the embossing and cleverly filling in the old ones. It was pretty hard work with a darning needle (I swear!), but Becker and his crew made thousands on the scam.

Naturally, it didn't work. It never does. Detectives did forensic work with photography . They took extreme close-ups of the check to show the subtle changes that had been missed by naked eyes. Becker and his boys were locked up for years.