Installer states success even when can't add couchbase user

In testing the root-less install, I tested without the existence of a couchbase user and ran into this:

[pkrug@localhost ~]$ rpm -i --relocate /opt/couchbase=/tmp/opt/couchbase --relocate /etc/init.d=/tmp/etc/init.d --dbpath /tmp/var/lib/rpm --nodeps couchbase-server-enterprise_x86_64_2.0.2-820-rel.rpm
/var/tmp/rpm-tmp.30098: line 11: /usr/sbin/groupadd: Permission denied
error: %pre(couchbase-server-2.0.2-820.x86_64) scriptlet failed, exit status 1
error: install: %pre scriptlet failed (2), skipping couchbase-server-2.0.2-820
/var/tmp/rpm-tmp.30098: line 12: /etc/init.d/couchbase-server: No such file or directory

You have successfully installed Couchbase Server.
Please browse to http://localhost.localdomain:8091/ to configure your server.
Please refer to http://couchbase.com for additional resources.

Please note that you have to update your firewall configuration to
allow connections to the following ports: 11211, 11210, 11209, 4369,
8091, 8092 and from 21100 to 21299.

By using this software you agree to the End User License Agreement.
See /opt/couchbase/LICENSE.txt.

[pkrug@localhost ~]$