What you are trying to point out is a martingale style of trading in whom forex traders will be adding more lot size to a single direction. Forex traders who are trading the forex field has to make a good plan with it, and trading with martingale method is never the best. The best in forex trading is for traders to plan their forex business with good strategy and apply the money and risk management to that strategy. That is what I know that will not cause aggressive trading for the trader.