Nothing is 100% safe; not even the best regulated mods are. I understand and accept the risks in what I'm doing, just as I understood and accepted the risks inherent in smoking, when I ride a motorcycle, or when I do any number of other things on a regular basis that are not 100% safe. Life is not safe and perusing safety above all else is not the life I want to live. Please let each individual make their own decisions as to what risks are worthwhile trade-offs for them.
Oh, I have thought about what I'm using. To me the biggest worry with most mechs is the pipe-bomb form-factor. None of mine are that. Well, actually, I do own one of those, but I don't use it. If there's no way for a mod to build more than a few PSI of pressure no matter how catastrophically the battery fails, you're simply not going to get an explosion; the worst you're going to get is a battery fire. If I were, designing, making and selling tube-mechs, I'd do actual venting tests. I wonder if anyone has ever done them? That would be an interesting project, wouldn't it?
Anyway, I wish you wouldn't paint all unregulated "mechs" with the same broad brush.