this is all true, but you cant always assume someone is cheating just because theyre good. i dont really play CSS too much, but in the same situation goes for halo 2 (when it hadnt been patched a while ago). just because somebody happens to be really skilled and always get headshots doesnt mean they have aimbot or whatever.
but ya, hackers usually try it for a week or so, then get bored of it. then when they come back people are always going to be calling them a cheater, and its hard to earn the trust back.