new Nick_Name;//имя авто/игрока

public OnGameModeInit

Nick_Name = AddStaticVehicle(id авто,координаты авто, цвет1, цвет2);

public OnPlayerStateChange

new vehicleid = GetPlayerVehicleID(playerid);    
if(newstate == PLAYER_STATE_DRIVER && oldstate == PLAYER_STATE_ONFOOT)    
{    
if(vehicleid ==Nick_Name)    
{    
if(strcmp(PlayerName(playerid), "Nick_Name", true) != 0)    
{    
RemovePlayerFromVehicle(playerid);    
SendClientMessage(playerid, 0xB50F00AA, "Ваш текст.");    
}  

if(vehicleid ==Nick_Name)//Вместо слов Nick_Name пишите, то что вы указали в new  
{    
if(strcmp(PlayerName(playerid), "Nick_Name", true) != 0)    
{    
RemovePlayerFromVehicle(playerid);    
SendClientMessage(playerid, 0xB50F00AA, "Ваш текст");    
}    
}  
}

stock PlayerName(playerid)    
{    
new PlrName[MAX_PLAYER_NAME];    
GetPlayerName(playerid,PlrName,sizeof(PlrName));    
return PlrName;    
}