1) Your brain does some fancy electrical things that tells your Eyes (The event system) to tell your Brain (The code) that something happened
2) Your brain then goes "Okay, thats a Warrior rolling on Cloth, he's a ninja"
3) Now, after your Eyes tells your Brain that an event happened and you finished processing, you do some more fancy electrical things to tell your Arms (The GUI) to type into WoW that the person ninjaed an item.
And thus, you have a perfect addon for reporting ninjas.
That sounds hard ^^ thinking and doing stuff at the same time.
Or be lazy make a big ass chatframe set font size zo 24, disable all default channels, enable Loot.
and BINGO you have a winner at the bottom of your chat after roling. Check class - Item. /gkick :)