Coinsbank for one and VaultOro. Suddenly my BTC balance reads zero. There was no explanation. You can see long lists of people basically depositing and then losing access to their account: https://www.trustpilot.com/review/vaultoro.com

It's pretty wide spread. People deposit for actual trade or perhaps interest and it only has to happen once for you to lose your principal. Exchanges are fractional reserve banks but far less honest than banks. Bank employees are probably the most honest people. I don't think it is the same over at most exchanges.

What I do to protect myself is firstly, to use decentralized exchanges as much as possible. This means Thorchain. Uniswap is something I don't often use because I am not interested in EVM chain tokens or coins. When using a CEx, trade less than $50.00 USD at a time. That means I may deposit 50 HBD, buy whatever and then withdraw. If the minimum deposit exceeds that $50, I just don't use the exchange.

I also tend to just leave value in each blockchain and perhaps spend within that blockchain for services rather than trading it. I feel comfortable trading within the Hive blockchain because it is always through a DEx.