Nidtendofreak
Smash Hero
The boundaries of the stage doesn't move at all: the stage itself becomes a hazard. Now you're just being subjective as well. It gives you a warning alright...just like how other hazards do. I can easily say "If you didn't hear the boom of the cannon, and couldn't see the cannonball go flying towards you from the background, you just suck at the stage." or "If you couldn't see that giant claw slowly moving around and getting ready to hit you, or that giant laser crosshair following you around, followed by it pausing and blinking before firing, you just suck at the stage." Frigate flipping DOES directly impact results. It's rare, but it happens. You are subjectively calling it a "boundary shift" instead of a "hazard" in order to allow it to be legal in your criteria, because otherwise it would be banned in it.The stage flipping is with it's quickly moving boundaries. However please note that isn't a hazard. Not only does it offer warning - it's not "luck" you died. It's just you suck at this stage. It doesn't deal damage nor does it altar the win results directly.
Unless I can stand in 1 spot and the stage MIGHT kill me like 1/100 times or something... but I don't think you mean it like that.
Also creating criteria for glitches that cannot be easily reproduced (or can actually be avoided if the player is knowledgable) is.. well.. not only impossible, but worthless to look into. The criteria covers the expected and only what is under it's definition. If you want to take into consideration glitches on stages and other things - you'd end up banning every single stage because I've seen a character fall between a stage on every stage. So by taking it this far (which, it shouldn't even apply to glitches or avoidable results) - we'd be playing a stageless game. Good luck with that.
This is why YI (B) is pretty much the only one up-for-debate on this criteria.
If you want to get technical, the moving platforms can also directly impact results. If you land on one after going into your free fall animation, and it starts to move back just as you land on it, some characters can't make it back. D3's standing back up animation after canceling his Up B takes a while for example. It can also kill Ness or Lucas's recovery attempt by colliding with their Up B at just the wrong time. Even more technically, the ballon on Smashville can do the same. How are these not hazards? Ness and Lucas mains using their Up B must make sure to avoid these things, otherwise they die. If you want a truly "hazard free stage list", those two stages must go as well. Otherwise it's actually a "minimal amount of hazards stage list"
At least one of the glitches are easily produced, and not fully avoidable. If you're forced to recover from a rather low point in the first stage of Castle Siege, and it starts to change to the second stage: you're dead. The transition floor will occur, and you can't get through it. You're forced into it like how you're forced into various other hazards in the game if your opponent puts you there (or if you're just plan stupid), like on Jungle Japes. The stages shift at a set time: the croc comes at a set time. There is no luck factor involve: you were simply forced there, or for some stupid reason you decided to hang out down there during that time period. There is no difference between the two, except that the croc comes more often, and the floor glitch has a bigger area.
As for the "fall through any stage" comment, I've only see that happen with D3 involved in doubles. That's caused by D3 inhaling, and being hit just as his opponent is being sucked forwards but isn't in his belly yet.