In any game with a competitive aspect to it, there's always bound to be at least a few people that hack to get an edge over everyone else.
I'd let you guys know if I'd run into any hackers, but Steam completely fucked me over and decided to update Black Ops from a shitty server that gave a speed of around 30kb/s. I tried the wonderful old trick of deleting the clientregistry.blob to force it to look for a new server instead of the retarded one it gave me, but that's just fucked it up and I'm now stuck at 30% on the "Updating Steam platform..."
Well, that's not entirely true. In the 10 minutes I spent looking at some other stuff and typing up this message, it went up to 32%. Woo, go Steam >.>