1. I do passwd -l <user>  and it does the right job -
prepending ! to the password in /etc/shadow
2. I do passwd -u <user> and sometimes,after removing the !,
it appends a few chars to the encripted password, rendering
the account unusable until a password change.
I use shadow passwords, no MD5, no nis, platform is i386.
Is repetable on user with 8 char password, on a user with 2
char is not reproducible.