Are you referring to editing your account? When you login to your bank, you'll usually see the first 6 numbers as stars and then the last 4 as shown. Since this number is optional and gets entered by the user and most banks will show the last 4 numbers when logged in, we don't see this as a security risk.
06/22/2013 10:17:59
Alex
User
Prohibit auto-fill for Last 4 Digits field
Doesn't it make sense to prohibit auto-fill for such a security important information as account last 4 digits?
