Open Buy & Sell positions at same time

Is it a good practice to open buy & sell positions at the same time on a day irrespective of market trend (advances/declines) ? Is this profitable in the long run ?

Then what...? Could you pls explain a little more on this with an example?

What I mean is to buy A & sell B one after the other in the morning irrespective of the market direction & close these positions later in the day.