I don't know if this will actually happen, but if it IS frozen, it's just temporary. So after, you can sell.
On a sidenote; I was thinking of selling after snapshot too, but actually I think it'll be wiser to hold. It will dip, but will come back much stronger. NXT has a great future imho
Selling off immediately and buying back in the dip could be a good solution as well. We'll see, transfering to Poloniex NXT does not work for me. It said that the address is not know or it asked me the public key. Any idea where to find the public key for my NXT address on Poloniex?