Unless of course the "Good" (non-fractional reserve) gateways had allowed people to redeem IOUs from other gateways before they realized there was run on; in which case their reserves (which includes IOUs from other gateways) are no longer sufficient to cover their own IOUs; despite being 100% funded.
It would still be their own fault, since they would not be managing their credit risk wisely.
And if you can only redeem your IOUs at the same gateway that you received them...then wtf is the point of Ripple?
You can still trade them with others through Ripple. As long as the exchange in question is solid, it's much quicker, cheaper and more anonymous than using the banking system. If the exchange is really solid, IOUs would only be redeemed infrequently compared to the number of transactions. IOUs are what allows you to trade in fiat currencies on the Ripple network.
So let me get this straight any gateway that allowed IOUs from other gateways would be taking on credit risk and in the event of a run would not be able to pay back 100% of it's own IUOs because of the IOUs of other gateways it held were defaulted.
You have said that it's people own fault for using these kind of gateways that are exposed to the above credit risk. So you would therefore say that all people should use gateways that only redeem IOUs that they issued themselves (and are therefore able to pay off 100% of their IOUs)
So lets assume all gateways only redeem their IOUs (because people would be silly to use a gateway exposed to risk you said).
Person A logs into Bitstamp, deposits Bitcoins, sends them to Ripple a Bitcoin IOU
Person B logs into Weexchange, deposits USD, sends them to Ripple a USD IOU
Person A trades their Bitstamp Bitcoin IOU for Person B's Weexchange USD IOU.
Person A logs into their own Weexchange account and redeems the USD IOU and withdraws their USD
Person B logs into their Bistamp account and redeems the Bitcoin IOU and widthdraws their Bitcoins.
Now ask yourself, what was the point in all that? When they could have both just logged into Bitstamp and done the trade directly without ever having to go to Ripple?