people who download movies and music via IRC using mIRC or any other IRC chat client are all susseptable to being traced. but only on networks where the server/networks owners are helping the fbi. in my own opinion. i dont see the fbi getting involved in the irc debate because network owners will not help with such investigations. i have my reasons to back this up but would just start a flame.
so. the answer is YES. you can be traced.