Interesting article. While it is entirely possible to do this, professional traders will soon move in and arbitrage any price differences between exchanges.
As competition increases, amateur exchanges that manipulate the price will suffer the consequences, for example, overpaying on the buy side because they've artificially inflated the price. Or traders will just move to another exchange if the spread is too high between bid and ask.
The delay with getting your money into/out of bitcoin is too long to allow for that kind of arbitrage. The exchange owner could easily get away with the described practices.
You just need an account with some liquidity on every exchange. You could automate an HFT bot that executes a buy order on one exchange and a sell order on the other simultaneously.
As competition increases, amateur exchanges that manipulate the price will suffer the consequences, for example, overpaying on the buy side because they've artificially inflated the price. Or traders will just move to another exchange if the spread is too high between bid and ask.