Yes, I would not expect it to be instant. BitStamp would need to have a strategy to transition back to equilibrium but in the meantime they would have a fractional reserve thing going on.
So, what would be the best approach to return to equilibrium?
I don't think they are unbalanced at this stage even. So
only when everyone starts to withdraw their BTC
and fiat there might be a slight problem. I don't see this happening. If they reopen quickly and restore customer confidence trading will continue and may even get back to normal levels. Business as usual.