Yeah I dunno. I don't think I can explain what I mean properly and don't want to re-watch a few hours of videos to refund the times it happened.
Basically the skater will be skating regular but then when they push it looks like they are pushing switch mongo but they then put their back foot back on the tail so this isn't about actual switch mongo.
I feel much less stable when I push switch Mongo at speed so I don't know if that's it. Or it just depends on the person.
Gardenskater77 and biaherl made decent points. It's probably just the idea was you set your front foot further back to do a bigger Ollie.
Even if untrue Im keeping my theory it's to disguise switch mongo.
I think the optimal pushing technique (if there really is one, because everyone will make their own way work anyhow) is front foot at the center of the board, and then whether you want to put more weight at the front or back (for stability or momentum) is dictated by muscular flexion, basically either standing up on your toes for more weight at the front or heel for more weight at the back. So sort of like subtly pedaling with that foot too and not just the one on the ground as to optimize the motion, sort of similarly to how a skilled swimmer would (with an extra object thrown into the equations I guess). At least that's how it feels like when I'm trying to push fast, e.g.. down a road and without tricks in mind. But it surely depends on the skater and their body type and stance, e.g.. how perpendicularly open their shoulders and how parallel their pushing foot are when they stand on a board.
So skaters placing their foot closer to the tail when they push sort of makes sense both for stability and speed. Probably subconsciously for most, it means that you're really pushing the skateboard/object ahead of you and building up on speed every time, whereas foot closer to the nose feels more like you're dragging it behind you and so mostly makes sense in spots where you have to go slow or in crowded situations. Imagine doing a one-footed wheelie, then a one-footed nosewheelie for an extreme example of what I mean. The first one feels like you're kind of driving the skateboard in front of you, whereas the second one is a lot scarier going fast for a reason, most of the geometry of the object you're riding is behind you and so the weights, friction and stability are different and you're way more likely to spin out of control due to how both the object and your body are designed.
I do swongo but mine is weird, I basically push regs with my front foot in the center of the board, maybe further to the back for stability and then once I'm done picking up my speed I hop back on switch. I can push regular switch but that's breaking 20+ years of habit and muscle memory and most importantly, right now I wouldn't do it to pick up speed switch exactly because I have yet to develop that control over the mobility and muscle memory in what's normally my pushing foot for the technique to feel just as stable as regs.