Sorry, but I am not handing over my private keys. This looks like a risky precedent. You should have thought of some way for the owners to prove they had the required wallet private key by generating a public key, or sequence of public keys, or sending dust or similar. Any protocol that requires the private keys is suspect.
You don't need to hand over your private keys, any more than you hand over your private keys when you run bitcoin-qt.
Your private keys are used to sign transactions, the same way as they are in Bitcoin.
The difference here is that all private keys which had non-dust balances on some date in May this year were sent 4 clams.