package mdadm doesn't respect /usr/sbin/policy-rc.d on installation

Package:
  mdadm 2.6.7.1-1ubuntu16
Tested with:
  Ubuntu 10.10, Ubuntu 10.04 LTS (all updates installed)

Problem:
  mdadm daemon starts after package installation regardless of the return value from /usr/sbin/policy-rc.d

How to reproduce (indention added):
  mkdir /some/dir
  debootstrap --arch i386 maverick /some/dir
  mkdir -p /some/dir/dev /some/dir/proc /some/dir/sys
  mount --bind /dev squashfs/dev
  mount -t proc proc squashfs/proc
  mount -t sysfs sysfs squashfs/sys
  cat > squashfs/usr/sbin/policy-rc.d << EOF
  #!/bin/sh
  exit 101
  EOF
  chroot squashfs apt-get -y install mdadm

Expected behaviour:
  With return value 101 of /usr/sbin/policy-rc.d, mdadm should not be started at all

Why this is a problem:
  Prevents clean bootstraps of ubuntu including mdadm, extra care has to be taken that the daemon ceases bevor building the distro and leaves unwanted log entries that have to be cleaned afterwards.