[KuHS]

Just use OnPlayerStateChange cellback:

Код:

public OnPlayerStateChange(playerid, newstate, oldstate)
{
	if(newstate == PLAYER_STATE_DRIVER)
	{
		new string[128],
			name[MAX_PLAYER_NAME],
			modelid = GetVehicleModel(GetPlayerVehicleID(playerid));
		if(modelid == 531)
		{
			GetPlayerName(playerid,name,sizeof(name));
			format(string,sizeof(string),"%s entered the tractor",name);
			SendClientMessageToAll(COLOR_ENTERVEH,string);
		}
	}
	if(newstate == PLAYER_STATE_ONFOOT)
	{
		if(oldstate == PLAYER_STATE_DRIVER)
		{
				new string[128],
					name[MAX_PLAYER_NAME],
					modelid = GetVehicleModel(vehicleid);
  			if(modelid == 531)
  			{
    				GetPlayerName(playerid,name,sizeof(name));
					format(string,sizeof(string),"%s left the tractor",name);
					SendClientMessageToAll(COLOR_ENTERVEH,string);
			}
		}
	}
	return 1;
}