I would agree that there is danger during the install and after the install. I don't agree that there is not an increased danger during the install if you are installing modules as root or modifying the version of perl that root uses.

My primary concern is about attacks that are easy to automate, difficult to detect, and provide root access. So I don't install modules for root to use unless they have been reviewed.

It is more difficult to exploit the capabilities of other users. Network usage, as sporty points out, is an example. This is relatively easy to detect, though.

The only data that I can think of that would be accessible to non-root, consistent between machines, and valuable would be found in ms systems. I don't have very high expectations for security in the ms environment, though.