This whole "long and short" at the same time started in the Spot FX world, where they called it "hedging." Primarily, the idea was that you could somehow time your long and short positions at the same time rather than admit to an understandable plain vanilla loss. In the USA, "hedging" is not allowed. All trades are offset with one another.
You may have different time frame strategies, and that could be administered in separate accounts, but it very unlikely that both instruments would be triggered at the same time. When people say they have a "hedge" strategy, either they paper trade or I know how the P&L looks like.
Not to make (too) light of it, but I always got a chuckle when someone in the scammy forex world would refer to it as "grid trading." "Grid trading gives you the AIDS" (Gay Related Immunodeficiency Disease).
Crass, I know.