Two examples that may help you:
http://www.sonic.net/~rfm/et/primo88.zip
http://www.sonic.net/~rfm/et/banez.zip
Demos are etpro, you will need to use etpro to play them back.
Please note that the person playing as primo88 in the first demo IS NOT the D|A clan member whose name he is using. In general, you should never trust ingame nicks as identification, especially with cheating scumbags.
Also note that not all aimbots are as obvious as the above. Many have adjustable settings and ‘humanizing’ options.
Judging soley on stats is almost always a bad idea, although it can can be an indication in extreme cases. (e.g someone with an SMG getting 80% acc and 3/hs kill against moving targets.) There certainly are players who can average 2 hs per engagement, especially if playing against less skilled players. hs/kill is even more deceptive, I can get over 2 hs/kill when I’m doing badly, because in many fights I get an HS in but don’t manage the kill.