As a very good FPS player, I get called cheat a reasonable amount of times - I usually play on the Jolt realism server, and to be honest, I'm pretty amazing with the rifles. Killing 3-4 guys is not impossible before going down, and on a good day, I kill 5 or 6 for my own 1 death. On bad days, 2 or 3.
Rather than play it like CS team deathmatch, I treat it like InstaGib (UT Game mode - one shot kills).
I charge about like a mad man - slow crawls is for suckers who want to get shot quickly.
You'd be amazed at how many people go slow when they should be going fast - you go fast when you aren't shooting, and go slow when you're shooting.
A high score does not mean cheating - on a normal game with a 250 score limit, I usually get 50 atleast. That's "good" - I'm a good player. But I play CoH when I have the connenction for it - at my parrents house, or when the wankers who run bit torrest here in my Hall of Residence turn off their pc's.
I expect players who play it 4 hours or more each day, every day to get 50 atleast.
I expect players who play an hour "now and then" to be at the recieving end of my rifle most of the time. That's life.
The sad truth is that there's a lot more "now and then" players than hardcore ones - and the hardcore ones utterly annhilate the noobs, which may look like cheating if you base it on a pure scores.
That said, I've only ever seen one obvious cheat - Hopefully with Punk Puster support coming in, cheating should decrease, but I don't think it's that widespread.