As with any game, if it is popular (and oddly enough, occasionally for unpopular games) people will cheat. Back in the day, cheats were easily accessible and nearly everyone had some to one extent or another. Today, they are SOLD to people (usually for around $20 USD) via hacker websites and other cheat-based websites. (note FPScheats.com)
Today I was sniped by someone with an assault rifle who was not even on my side of the map with a shot that was not only insane, it was impossible as there was no way for him to even see a glimpse of me nor for him to be able to get 1 perfect headshot with his weapon from the distance we were apart. At maps end, he had just under 100 kills and 7 deaths which, regardless of skill, is also damn near impossible at this point on Bad Company 2.
I hate cheats and pity them at the same time. Does it really make them feel like they have skills when they have to PAY for cheats ? Sure, I am sure we would all enjoy it for a day or 2 but, after that, at least to me, it seems like it would be VERY boring and I would most likely stop playing the game anyways. In the end, what is the point ?
Every Battlefield game (and probably every other game with rankings) has a history of having the top 10 – 20 players be the ones who cheat the most.. BC2 is no different in this regard and I doubt there is much that will be done or that CAN be done. For every cheater that gets banned, a few more pop up. For every update to anti-cheat technology (i.e. punkbuster to name just one), they update their cheats and so it continues.
In the end, all we can do is hope the server admins are watching and kicking accordingly or leave the server.