Wallets didn't have password protection 4 years ago.
Pure win.
Not so fast. Fairly ancient wallets seem to load fine into the modern codebase. Seems possible that an older wallet could be encrypted in anything past 0.4. I've not tried it though since I think that encrypting wallets using bitcoin-qt is stupid in a lot of cases. In fact, I've never even run anything but straight bitcoind.
OTOH, it seems equally or more likely that the whole $10M loss is a sham story.