Can you explain precisely what security risk there is from demonstrating proof of reserves?
they don't really owe anyone to prove it as well
They are a publicly listed trust. They actually do owe it to public stockholders to prove that they have the reserves.
It's apparently true that they owe it to their investors. Opening up can easily cause panic among holders leading to massive withdrawals and the collapse of everything. Perhaps the best way for proof of reserves to work is with a private auditing institution only
Why would this happen if they actually have the reserves? If they don't have the reserves they are committing a crime, and it's not about risk for investors but risk for themselves having to face the consequences of their crime.