Debian unstable chroot security issues

[This page](http://wiki.debian.org/Debootstrap) describes how you can use the debootstrap utility to install a base Debian unstable/sid system on an existing Linux machine. The new install is accessible using chroot. When doing this, what security issues should be kept in mind? For example, what needs to be done to stop background/startup processes from starting in the new chroot or otherwise interfering with the main system?