Perhaps that's what separates "conventional" medicine from new-age/alternative - the scientific, "laboratory-tested" evidence?
With religion/spirituality of course, there possibly might never be this "scientific evidence", well not in the foreseeable future anyway. That's probably why the terms "belief" & "faith" exist no doubt.
Personally, i'm not too concerned about "proof". As i almost never buy anything, i'm not worried about being "ripped-off". I usually just read about all these things out of pure interest, or sometimes out of searching for answers to various problems, or to try to gain some spiritual progress. I am a fairly extreme perfectionist, but in these areas i seem content with the imperfection of not knowing if they are really true or not. I find that this makes them more interesting or exciting. And if they help me a little, that's fine, if not, that's also fine.
As for knowing whether they are true/factual or not, sometimes i flip between yes/true & no/false, but generally i start off as believing that it's possible or probable/likely to be true/correct (ie give benefit of doubt to), and then as i read (and maybe apply it in my own life) that belief in the degree of truthfulness will gradually move in one or the other direction.
About Emoto: "Hado" is some kind of "life force", and Emoto hasn't "invented" that, so that concept is "free" (no monetary gain involved), and is an idea shared by many people & groups out there, so theoretically that "hado" is more likely to be true than the water-crytals stuff. He is a scientist, and has supposedly "invented" (actually has just "uncovered") this thing about water crystals being able to be influenced by human thoughts, and drinking specially-created water being able to give us health benefits.
I am giving him the benefit of the doubt, and i believe (from what you've stated above) that he could be trying to keep his methods secret for commercial reasons (like KFC never giving out their secret recipe).
Also, he is only a scientist, not a metaphysician, energy worker, or anything else, so maybe even he himself doesn't have all the necessary "tools" to bring this project of his to a "complete, comprehensive conclusion"? He might still be "missing" certain things about it. Who knows. But he certainly has uncovered something special, it seems. Time will tell. And the proof will be in the pudding...