This is exactly why I believe that large scale traders and institutions don't want to deal with crypto currency exchanges, but rather wait for other institutions to set up trading desks, and I can't even blame them.
Every year we're seeing how multiple exchanges go down and the operators take a run with people's funds, or that the operators claim to have suffered from a hack, while it was an insider job....
When it's entities like the ICE and Fidelity and Citibank holding custody instead of lone exchange operators or Bitgo multisig, there will probably be fewer exit scams like this. However, there will still continue to be hacks and embezzlement attempts by insiders. One of these Wall Street custody solutions will eventually get compromised and that'll trigger a major controversy about the viability of Bitcoin securities and physically settled derivatives. I just wonder how big the market will be and how much will be in custody when that happens.