This seems like a legal-enough scheme:

- Take people's money to form [insert random Crypto bank-like scheme]

- Invest the money into high-risk investments

- If investments don't pay off, declare bankruptcy. You were gambling with someone else's money

- If investments do pay off, you're rich. You just need to return other people's money, but you keep the upside

There are a ton of schemes like this in traditional investing, but limited to scamming "sophisticated investors" or "accredited investors," depending on the scheme. For crypto, it seems like regulation hasn't caught up, and companies scam random consumers.

By "legal enough," I mean legal enough that scammers can convince themselves they won't land in prison.