Kick

The kick console command will disconnect the specified client from the server, but does not prevent the client from reconnecting. This command is often used as a warning by admins (or masters prior to 1.0) who don't want to ban for minor or first-time offenses. To get rid of continually disruptive (cheating, team killing, etc.) players, the ban vote can be used.

It's possible to votekick players from a server, but they can easily come back and continue being disruptive due to the lack of a voteban.

Usage
Open the console and type in, following by the player's client number and a reason (in quotes).

Possible screen messages
ExamplePlayer1 called a vote: kick player ExamplePlayer2 could not vote: no permission

ExamplePlayer1 called a vote: kick player ExamplePlayer2 invalid reason