This is my assumption:
These sites act like banks. They take all this money in from players and keep a percentage of it on hand for people who want to cash out. The rest of it they invest. Back in the day many many years ago before banks were FDIC insured, banks would keep a 1:6 ratio. They felt that that was a safe amount of money to keep if there was a high demand for cash. A 1:6 ratio would obviously not be enough in a large bank run (its when a major chunk of their clients try to withdraw their money,) and that bank would go out of business. Today, with FDIC insurance by the US government the ratio is now closer to 1:20.

Now if I was to run a poker site I too would keep some cash on hand, but it would be very wise of me to invest the rest of it. I would bet all these poker sites do just that. Now what their ratio is, I do not know, but I would bet it is much higher that 1:6. My guess is, with the lawyer fees, the seizures, and add in all these non US costumers who have successfully transfered their funds, and those funds that are pending, they do not have enough cash to pay off all their clients.

What all this means is that these sites will have no choice but to go bankrupt.

This is just an opinion, but this whole thing really looks like a massive bankrun to me. I have kissed my Full tilt and AP cash goodbye. Today I play a nice live cash game where I know I get to cash out at the end of the night.

BTW, if I was the owner of a bank in a bank run I too would be saying that your money is safe, and try to make out with as much of it as possible.

-Beck