Pretty simple, if a person finds that their computer has been logged into, like for example the detective leaving the device on, would prompt the person to change their pass. same for the government database pcs. where if they find that someone was rumaging around who didn't have access, will promptly change the password.
or maybe the enforcers just change it every day or two, as a security measure, we see signs of people forgetting it with notes, so it would make sense that it would also happen proceduraly.
with this the player would have to re find the code, or just be more cautious when using crunchers as to not alert the owner of any tampering,