This kind of thing happens a lot. I've had players insulting me while I'm recording a demo of a hacker, good idea that, insult the admin that is going to ban the hacker and not the hacker[:@]. Everyone hates hackers and wants them off the server so I understand the "ban him already" comments, but calling me names? How is that going to help?.
I had one player tell me proudly after I connect to spec a guy with a massive score "I told him you were admin so he left", like it was a great thing to have done. Well done fella, now he can come back any time he wants, good job. That is why I usually change my name before connecting.
The best thing for players to do if there is an admin on and you think someone is cheating is to use chat @ message, to talk to admin only like Castor said. And if there is no admin on then see:
http://www.spawnpoint.com/What_to_do.../m_1354/tm.htm
It makes an admins job much easier and helps keep the servers fairly hacker free if players do this.