It is the nature of the group buy, in keyboards and in other hobbies, that significant risk is taken on as the end purchaser. This is not a retail process. The expense and risk is high because a small group of people are seeking something that otherwise isn't commercially viable. It's worth always remembering the trade-off of wanting something special. And if you can't afford to lose it, you probably shouldn't ever join.
One thing about this buy: Kin25 only took deposits. So as far as making it rain, I don't think so. He would be a very poor scammer indeed. More likely is his family, his job, and a couple of manufacturing problems all snowballed into something he is having a hard time handling. Maybe he won't ever be able to make it right, and maybe he will. No one really knows right now, possibly including Kin25 himself. Which might explain why he won't post.
As for a system to prevent problems: you can't. Make everything retail and none of the special projects happen. Failures have come from new members, and members who have run many, many successful buys. And, in complete honesty, maybe people like me are the problem. I'm not pleased with how this has gone so far, but despite everything saying this is a sinking ship, if Kin25 sent me an invoice tomorrow I'd pay it. I'd still rather have the keyboard than my deposit back. And therein lies the rub: I'm not the only one who thinks this way, possibly making it a little too easy for bad projects to fester.