Users who are not yet in LDAP are allowed to edit their LDAP
information, such as username. This means you can sign up as a DM with
one username and then change it before applying to be a DD (see
kaction/iu for an example), which leads to confusion. Either we
shouldn't pay any attention to the username before it is set in stone in
LDAP (i.e. don't include it in account requests etc) or, preferably,
once someone becomes a DM they shouldn't be able to edit it any more.
Evil will always triumph over Good, because Good is dumb.