CentOS - Nov 2012 - How to prevent host boot problems with virtual client disk?

I added one new disk to my Centos5 machine and I want to dedicate this
disk to one of my virtual machines (also Centos5). After I added the
(empty) disk the machine starts up fine and identified the disk as /dev/sdd
It makes we wander what might happen to the host during a future
(re)boot. The new disk will get a partition table and logical volumes,
all which should be private to the client. The (KVM) host however will
also see this disk during boot. My host volume group has a non standard
name to prevent collision with the volume group name of the client
(VolGroup00 for instance). I know I can even ignore the client group all
together on the host.
Now I am afraid that during boot time the host sees /dev/sdd as the
first disk and tries to boot from it (bios update/reset for instance).
Is this a real risk?
My question is thus, how can I prevent that this (physical) client disk
can be used for booting by the host without messing with the
bios/cables? Should I first partition the disk and give one partition to
the client (the disk than has a second disk layout stored on this
partition). A similar thing can be done with a logical volume, but is
this wise?

Theo