There's another way to arbitrage with bitcoin?

In this link I see that they are doing somthing like buying BTC in cheap exch and sell BTC to USD in another, when price correlate, sell BTC to USD and buy BTC in the other, without doing transfers between exchanges, someone tried it or it is possible?

http://obsidianexchange.com/cross-exchange-bitcoin-arbitrage/

And look at this shit, it is possible to do arbitrage with BTCUSD-BTCEUR agains EURUSD?

[img=http://s12.postimg.org/h57ix7149/btcusd_eur_arbit.jpg]