Because the chroot call can only work for root, when I tried to install a
package into a temporary directory as a non-priviledged user it failed to
chroot and attempted to install
into /.  RPM should probably detect this case and signal an error, or at
least check the
result code from chroot.

It is unfortunate that regular users can't do this, but I suppose that is a
complaint for whoever
decreed that chroot shall only work for root.