Qmail refuses to deliver if the user account dir is world-writeable

[Foo Ji-Haw]

How can I make qmail deliver incoming mails anyway, to user accounts which
are world-writeable? Right now, it does this:

Jul 11 12:53:09 markus qmail: 994827189.053526 delivery 85: deferral:
Uh-oh:_home_directory_is_writable._(#4.7.0)/

Any help is appreciated. :)