In some way it is a security feature... Some keyloggers are set to record when a combination of '4 number + space + 4 number + etc'. This is why my bank removed the first 4 numbers (which are common to everyone) when I login to my account. Also, they switch automatically to the password field as if it was a continuation of the number.
That's silly, because the same keyloggers can recognize sequences of 16 digits as a credit card number, particularly since they can be easily checksummed for confirmation.
I disagree. It would be easier to write keylogger which reads 16 sequential digits, computes a checksum and then emits a UDP packet to a hardcoded IP address.
