few "investors" or perhaps nobody will see their bitcoins back. He will now say, I have an unexpected number of withdrawal requests; fulfilling them will take some time, etc. He might even fulfill a few small requests to buy himself some more time. But then it's game over.
Why the hassle of making announcements then? If it was just a ponzi coming down it would have been better to just vanish in the air with the whole loot a.s.a.p.
Well there's already people making a stink about withdrawals, he's gotta tell them something. Like you said, if it were a ponzi.