There are places like mytrashmail.com which would make that sort of thing easy peasy.
You gotta think, some people aren't doing it for the stats, they're doing it to annoy other people or just for their own laughs.
If you played a game on say headquarters, if it's as easy to kill as it looks, I reckon you'd get to like level 55 in less than a week if you were dedicated enough.
Not condoning it, just sayin'
Freeze jumping i believe?
If you're playing COD4 on the PS3 then it's not worth moaning about.
Only seen this a few times on the 360, but it does happen. Latest one was somebody hiding in a rock in Creek. Filed a report and avoided, simple. Not as widespread a problem as the Turbo controllers some ***** are using.