>If they need liquidity for the network to operate, they should allow people to provide funds for liquidity or operate as middlemen.
Being a market maker (providing liquidity and being able to transact between currencies) is a feature of Ripple; I'm assuming it's part of Stellar as well.
Well you can turn the feature off if you want. You can also set the "quality" of a given issuer. This means that you could apply a discount to the mtgox credit so it would swap out at a discount. But really it will probably just be turned off by default
If they need liquidity for the network to operate, they should allow people to provide funds for liquidity or operate as middlemen.