This works. By moving the F4 closer to first she can make the play on the runner much closer and quicker then trying this play at second base. Often times it is while the runner at 3rd is still moving back toward 3rd base. If you make the play at second it allows the runner at 3rd to be prepared to go as soon as the ball leaves the pitchers hand. Its usually a longer throw from the circle to second base then it is from the circle to the spot you have F4 stationed for this play, its also a shorter throw for F4 to make back to the plate. I have seen this work many times for one out and the runner at 3rd does not advance and I have seen the out at home, way more times then I have seen the run score.Depends on the age and skill level. Because the shennanigans that 10u/12U coaches run on this play don't work once girls are strong enough to make two good throws in time to get both outs.
If you don't have kids who can make two outs here, then you can try throwing the ball immediately to 1st base as a way to forestall this. An experienced base runner will know that she can start towards 2nd base on the throw from F3 to F1 so it isn't a complete answer but can sometimes make the other team pause at the very least.
Our standard defense on this was to get the ball back immediately to f1 then bring f4 close to 1st base and put her in a position (15 ft away , just behind baseline) that forces the batter runner to round 1st in front of f4. If she starts to go then a throw immediately to f4 who then either makes an immediate tag or throws home immediately to get the other runner from third. The idea is to keep everything in front of her and timing of the throw to the 2nd baseman is key so it needs to be pracitced over and over with a live runner for the pitcher to get the feel of when to throw. IF the opposing team sees you in this prevent position and respects your ability to make the throws then they likely will not test you. We got two outs on this play with a 14U team playing defense and never got two outs on a more standard 1st and 3rd steal situation that year so it's a high risk low reward proposition for the offense if they respect the defense.
Use the rules of the game to your advantage. Look back rule goes into effect the moment the batter/runner touches 1st base. At that moment, if no play is being made, the runner at 3rd must immediately return to 3rd base, or head to home plate.
So even if you get the ball back to the P the LBR does not start until the B/R reaches 1st?