Awesome
Having read through this (like I have read all of your posts, Emblem Lord), I cannot express how appreciative I am of your guides. I have always thought of myself as a high-moderate Marth player, but I am still learning little things from you each time I read one of your posts. So thank you for helping me improve my game! :D
That said, I don't recall any mentioning of follow-up edge guarding. My friends and I are not experts, mind you, so I cannot say how this would work in competitive, tournament play. However, I like to follow my opponents off the stage if they look to be recovering, and fair them before turning around then using the double-jump and Up-B to recover. Countless times I have drawn a groan from my friend's lips as the tipping nudged them just far enough away from the ledge that they cannot recover. From so far as I can tell, most characters cannot retaliate through this nudge tactic without sacrificing their ability to recover. And if they airdodge, then Marth is still capable of jumping+Up-B'ing to recover exactly the same way he would if the nudging took place (none of my friends have ever airdodged the nudge, so I can't say how effective it would be at stopping the technique).
Nonetheless, in 1-on-1 match-ups, this nudging tactic has, I believe, won me several games because I could safely ensure that my opponent dies without taking a hit myself.