Here's an example of why fingerprint recognition does not make for very good biometrics.
return to the use of keys after the cutting-edge technology repeatedly
The system, which is thought to have cost over £3 million, used
fingerprint recognition to activate the locking system at the
high-security Glenochil Prison near Tullibody, Clackmannanshire.
After typing in a PIN code, prison officers had to place their
finger on a piece of glass. Once the print was recognised, they could
then lock and unlock prison doors.
However, problems arose after a prisoner demonstrated to wardens
that he could get through the system at will. Other prisoners had been
doing the same for some time.
Over the past few ywars, I've seen how-to articles describing multiple ways to overcome fingerprint biometrics.