COD mw2 in a nutshell: Boosters who claim they weren't boosting

I've been following these two little brats all morning. My dad started playing and while I was watching him play I noticed boosters in the kill-feed. I proceeded to ultimately destroy them. Later, they invited me to a private match, teamed up on me, and I still won against them. alexisriku's friend got pissed off and kicked me