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.
That sounds obvious, until you rephrase it as "it's gives more security if you install modules as a non-root user". Sure, it might matter if no UID that can cause havoc ever runs the code of the modules installed, but if so, what would be the point of installing them? My point is that the danger doesn't stop that "make install", it's isn't that you can relax if you get a prompt back after typing "make install". That's only when trouble starts.
The dangerous part of opening a lion cage isn't the act of opening the door - the danger only starts when the lion gets out of the cage.