How did the Four Horsemen accomplish their second trick?

In the airplane scene, right after the first act when they are with Arthur (Caine), they play mentalist tricks on him. Daniel tries to guess incorrectly about Arthur's life. Each time, Arthur himself presents the correct information -

Daniel: You had an uncle who had a manly name...?

Arthur: No, his name actually was...

So you can see that Arthur was just passing information to the Horsemen, which in the end, contained his bank account information that helped them access the money.

I'm sure getting his account number wasn't much of a problem - he was their sponsor after all. And then, trying to get his password, his security questions, etc. would require some knowledge about Arthur himself. Which they got with their time spent working for him, and through the mentalist tricks. The scene on the airplane shows exactly how they could get information that they wanted.

During the show, when it is finally revealed that they are giving away Arthur's money, he is baffled as to how they got access to his account. That is when they tease him about his security questions - mother's maiden name, first pet, etc. And then sarcastically ask him how they could have gotten that information. He would never have given it to them. When in fact, they cleverly got this information from Arthur with mentalist tricks played throughout. They had a lot of time to gather this information considering that they had everything planned out right from the beginning. So they had the time they were first introduced to Arthur, right till the second show to get all that information.

There wasn't much explanation for this trick because there really wasn't much to it in the first place, they just hacked his bank account and transfered the money to the accounts of all the people in the audience, which they knew, since they selected them especially as guests for the show beforehand.

Given that the movie made use of some very elaborate technological gadgets, it isn't hard to believe them to be able to hack Arthur Tressler's bank account using the usual computer hacking magic known from the movies. Arthur Tressler has been their target (and thus that of Rhodes, since he set up their whole plan) all along, since they wanted him and his insurance company to pay for what he did to the Katrina-victims. In fact, they actually tell Arthur right on stage how they managed to get his password by asking him some questions and doing some mentalist tricks:

Arthur: Hey, did you do this!?

Jack: How could we, Arth? We don't have your password.

Henley: We'd need access to information we could never get our hands on...

Daniel: Security questions for instance... Like, I don't know, Your mothers maiden name or the name of your first pet.

Merritt: Where would we get that information, Arth? You'd certainly never tell us...

To Arthur they were just a bunch of talented illusionists that can perform a good magic show. He never knew they actually robbed a bank in reality (and if they did, then only to do a good magic show, which was in Arthur best interests). He just was a normal businessmen that sponsored the Four Horsemen, providing the resources for their show and getting a share of the ticket sales. He wasn't really aware of the fact that they had quite some technological backing to their advantage, let aside an ingenious plan to betray him and bite the hand that feeds. They were his employees in the end, no reason to assume they're thieves or can do real magic.

Here is how the trick was executed (In 6 Simple Steps):-

Step 1: The Four Horsemen befriended Arthur Tressler a businessman who was too proud of himself to understand their wickedness. He also understood everything the way the Four Horsemen wanted him to.

Step 2: By accompanying him for a long time, they came to know a lot of personal facts about him. For instance, consider the plane scene, where Arthur unconsciously provided them with his personal facts.

Step 3: My best guess is hacking was not at all needed by The Four Horsemen. We all know if somebody looses his password, system asks the owner to provide with answers to some preset security questions which are not hard-to-know facts for close persons with the owner. Similar thing happened here. They furnished all the necessary information that has been storing in the Four Horsemens' database for a long time, asked by the system and possibly they changed or retrieved the password of his account. All this thing was done according to me just before the show started so that Arthur does not get any chance to know about this burglary.

Step 4: The Four Horsemen did not know about the true identity of Rhodes; so they arranged to stop him after the revelation beforehand, so that they can get the chance to flee.

Step 5: They shackled Arthur when he realized The Four Horsemen went berserk.

Step 6: They knew about the tracked device all alone. It was just a simple trick, they managed to misguide Rhodes during the chase.

Personally, I think this plan was never that hard to understand, so producers did not put effort to clarify it since the whole process can be easily imagined by the spectators. This is the best we can make out from the hints left in the movie.