My 24 hour system got whipped today however the shorter term (4hr) system did great. A couple of days ago the situation was reversed. As a system trader you can't afford to pay attention to noise. Let the system do its work. If it stops you out then so be it. That is part of the game. If you try fiddling with the system rules then you no longer have a mechanical system.
My advise to any one who wants to trade a mechanical system is to stick to the rules through thick thin. If you have a robust system it will keep you ahead in the long term.
The news only temporarirly affects prices. You can see that when the market overall is intent on going in a certain direction the news is only a bump in the road. Often the market tips its hat beforeh as to direction.
Of course that's only my view all of 7 months of Forex trading but....there it is.