Are interns valuable or pain in the *&#?

I will be doing an internship next year as part of my college education. We have been warned that networking interns are viewed as a pain for the net admins that are mentoring them because the students are not allowed to touch anything or work withthe company’s password management, etc.

Can anyone share with me what they look for in interns that are hired at the end of the internship? What good things AND bad things are you looking for?

Thanks,
Scott B