Yes, I agree that my idea is not applicable for all EAs. I just voice out this opinion because I see some recent EAs which do not have stoploss and thus open orders for a long time. From their back testing results, it seems very good but if you think more deeply, they look good not because their indicators system is really good but because if the marking is ranging and if you hold your orders long enough, it is likely that you will see it in profit one day, no matter under what conditions you opened your orders.