It's all fun and games...
Until you come across a pc that has a boatload of extremely illegal crap on it...
I used to be a systems administrator for a small collection of schools when one day I decided to upgrade all administrative pc's with a new anti-virus package.
One particular computer caught my attention because the amount of free space on the drive was extremely low, so after a quick search revealed a hidden directory within the "tempory internet files" directory full of pictures of grown men having sexual intercourse with young children, I decided to take a small trip to the local police station during my break.
After a long talk with a police officer it was decided that I should take no action and tell nobody for the time being and just continue to gather evidence.
So after verifying that it indeed was this one particular person who was responsable for this and making copies of proxy-logs and everything the police finally came round to take the computer, proxy-logs and an external harddrive as evidence.
The guy was arrested the very same day, management and other colleagues were pissed at me for weeks because I didn't tell them what was going on until it was too late...
Turned out that not just this guy but also 3 other people within the organisation (including 2 members of said management) have been sharing this crap amongst themselves for years !
I'm glad I don't work there anymore...