It isn't only jerky unfocused movement, that's at an even high level than what this guy was doing. He pretty much swam up all the bullets. Looking at the replay it just looks like he's tried the stage itself once or twice; he moves into waves utterly brainlessly and swims up everything. It's ridiculous to say that you can't prove it. Yeah sure technically you can't prove a record of a sequence of button inputs, but you don't need to technically prove tool-assists to know that it is indeed tool-assisted.
I mean you can even look at it like a scale of "ability" of tool-assists. I could go through easy mode of a Touhou game with tools, provide a replay and you wouldn't even
be able to tell it was cheated after watching it. It's when you start making obviously daring (read: retarded) decisions, read bullet patterns and react at superhuman speed, twitch unfocused in ways that are simply absurd, etc that it becomes easy to tell if someone cheated. You can even get to the point where the person makes a bunch of awesome dodges, doesn't
realize what comes next due to inexperience or sheer rashness, and dies by walling or confusion.
http://www.youtube.com/watch?v=wmKMg92WFpsIf I tried to pass these runs off as real, would you believe me? No, because it's fucking ridiculous. You can't "prove" I cheated, it's just glaringly obvious. This is just on a more grandiose scale than people who use tool-assists to cheat. Putting aside my frustration at people who cheat to complete a game, cheating for the purposes of receiving a social reward, whether it be praise or winning a contest or whatever, is just terrible. It's why I don't like telling
anyone how to tool-assist Touhou, and why I generally don't like these kinds of information publicly posted.