Here are some Facts:

1. No one has established that any payments were actually made, the only claims have been from those profiting from the smuggling i.e. the smugglers, the indonesian police and SHY, all of whom are wildly unreliable.

2. Stopping the People trafficking is based on "asylum seekers" paying thousands of $ each to reach Australia. Paying this money to end up where you started is a seriously bad investment that is unlikely to encourage further customers.

3. If payments were made as claimed, they were not to people traffickers, just to drivers of the boats, so it is difficult to see how these payments would incentivise the smugglers to send more boats,

4. Finally, given that on the high seas the UN charter on refugees does not apply, and the interception of human traffickers is legal, it is difficult to see where paying the Indonesian drivers of Indonesian vessels to return to Indonesia with passengers that departed from Indonesia can be illegal considering that payment of criminals as informants to reduce crime is accepted practice world wide.

Do an analysis not name call. Suborning the employees of people smugglers with a small bit of money to turn back means the People Smugglers model is further trashed. It is good Tactics to the Strategy of "Turn Back". "Customers" are going to be knocking on the doors of the Indon Factors wanting their money back and telling others the crew shafted them.
An encouragement to smugglers, NOT, I just wish the nongs who believe this were running people smuggling, it would have collapsed years ago.

I don't trust the Indonesians, many are making money out of smuggling illegal immigrants into our territory for which the Australian tax payer pays the bill. Look at Europe? I know that Indonesia is a large region to police, but somehow we have to stop it. If they are economic refugees some who can not speak English it is easy to con them into how they will be received in Australia. Remember some years ago when the navy turned back people in a orange life boat. One disgruntled man said on TV ' We are Australia's problem not Indonesia, and Tony Abbott will regret it and he will be killed'. Oh yes. The smugglers are believed to have been handed $30,000 to take them back. I think the Abbott government knows more about this than any person not in the loop. There are security questions and that is their affair. We are NOT dumping them in the ocean like some of the smugglers have done in transporting folk to Europe from North Africa and the like. Why don't the UN intervene? Seems they just want to complain about us regarding AGW and our climate policies and the UN Climate change fund, and our treatment of refugees. They have stopped the boats so stick that up Shorten's pipe and smoke it.

Those who read my posts know that I oppose the presence of Australia's navy near Indonesia altogether, that we rather allow boats to reach Australia (then deal with them by not giving them anything).

However, given the existing policy of stopping the boats near Indonesia, can we really tell that the money paid to the crew was for turning the boat back, rather than, say, in return for information they provided about the smugglers and other boats?

Reading between the lines, a dodgy activity at any time, it would seem
to me that the smugglers sent the boat(s) to sea being well aware that
they were very unlikely to reach New Zealand.
How skilled were those Indonesian crewmen ?
We are not now talking about navigating around the Indonesian islands.
Would they have had the experience to undertake a Pacific voyage ?
Did they more than a GPS for navigation ?
According to the report from the Navy/Customs they were concerned
about the seaworthyness of the vessels and the engines reliability.
Was the fuel tank large enough ?
These questions might be more usefully commented on by Hasbeen there !

In view of the questions I suggest that there was only one prudent
course for the commanding officer to take; send them back by hook or
by crook, to coin a phrase.
They almost certainly saved all their lives.