if(Minecraft.thePlayer.username.equals("banned username"){
	//prevent user from using mod, maybe fuck over his world while you're at it.
	//Minecraft.thePlayer.getPlayerSpawnCoordinate(); will return the location of the player's bed,
	//(or crash the game if it's a new world).
	//world.setBlockWithNotify(i, j, k, 11); will replace a block with lava.
	//Now just replace the whole area around the bed with lava.
}