yes it is a method followed by many traders ever i follow it sometime. i keep some of my balance in two different exchanges and i buys from one exchange and sells from another. its a bit of pain thought because we have to constantly keep track of everything and even small mistakes can bring huge losses. so just be careful while doing this.
And what do you when you go completely empty on btc on one exchange?
You have to buy from the other. And if the price goes up your actually ending up doing the same thing on both.
The good part is that at least you have not put all your eggs in a
basket gox crushing machine.
Having all your funds sitting like ducks on exchanges is just like asking for trouble.
This is actually a very viable way of making money off trading. You just need to know what you're doing. it's called "Arbitrage".
And it's also a pretty viable way of falling into a trap. Be it bull or beartrap or goxtrap.