The problem is that technology is advancing so fast, it has become incredibly easy to create false documents.
Color copiers reproduce most checks beautifully.
Scanners, computers and printers create checks that look as good as the original. Banks are trying to keep costs down, so tellers are encouraged to hurry through each transaction - they don't even have to verify signatures on checks. Changes in the Universal Commercial Code have allowed liability to be shifted from banks only, to the party most able to prevent the fraud. Just a few inexpensive features can indicate that you have made the effort to prevent fraud, shifting responsibility away from the you and back to the bank.