bubbaking
Smash Hero
Well this is just my speculation, but it's very similar to DDD's CG. Falco can go for just one more regrab if the opponent is just barely offstage or he can go for the spike right there. If he just goes for the spike and the opponent doesn't SDI, he gets spiked regardless and Falco doesn't have to risk going for a grab that may not have been possible, but he also risks making it easier for the opponent to SDI back onto the stage. However, if he gets that grab, he now has perfect spacing and has made it more difficult for the opponent to SDI back onstage. It's like how DDD's CG can send the opponent just barely off the stage, so we go for one more grab, and in fact, I believe that is the premise of our infinites. This is all just guesswork regarding Falco, though. I don't actually know the answer to that Q for sure.
Edit: Actually, another piece of speculation that I have is that it involves Falco walking for his CG instead of running. As you probably know, Falco can walk for some of his CGs and he can even boost pivot grab for some. All of these things would affect his spacing. For instance, during a CG for which he could do walking grabs, if he does a dash grab, he'd skid more. Again, it's like how we DDDs can vary our spacing during our CGs by switching between dash grabs, SCSGs, and, for the chars we can pull them off on, walking grabs. It's how good DDDs can reliably set up the infinite on chars like Wolf. Again, this is just speculation regarding Falco.
Edit: Actually, another piece of speculation that I have is that it involves Falco walking for his CG instead of running. As you probably know, Falco can walk for some of his CGs and he can even boost pivot grab for some. All of these things would affect his spacing. For instance, during a CG for which he could do walking grabs, if he does a dash grab, he'd skid more. Again, it's like how we DDDs can vary our spacing during our CGs by switching between dash grabs, SCSGs, and, for the chars we can pull them off on, walking grabs. It's how good DDDs can reliably set up the infinite on chars like Wolf. Again, this is just speculation regarding Falco.