The price discrepancy between the exchanges is kind of strange. The price on one has been up to five times higher on one than the other. It has narrowed now but is still large I think three times or so.
We are talking about IOU lisks so it's normal.... only a 'limited supply' is available for the trading.
Plus, there's no way to arbitrage. The IOUs themselves are not fungible, so there's no way to withdraw or deposit them.
It is true that the pre-launch IOUs cannot be withdrawn or deposited. But what do you mean they are not fungible? And I know what fungible means, so I'm not asking you to define it. I'm asking what you think it means in this context.
Sorry, I should have used the word "transferrable." I meant "non-fungible outside of each exchange," in the sense that each exchange's ICO-buy is frozen until Lisk launches. But that explained, "not transferrable" would have been better.