Twenty four hours on, we now have a clearer idea of the circumstances in which Australian human rights lawyer Jen Robinson was stopped at Heathrow Airport on her way home to Australia, told she was on an “inhibited persons” list and that she would not be permitted to board her flight without approval from the Australian High Commission.

But not why she was stopped and on whose authority.

Robinson touched down in Sydney this morning and was looking forward to seeing Attorney-General Nicola Roxon at the Commonwealth Lawyers’ Association conference, where both are speaking.

Robinson, who has spent most of the last day in the air, has clarified that she understands no call was made from Heathrow to Australia House before her check-in was approved, despite Virgin Airlines staff and a security guard insisting she was an “inhibited person” who had evidently done something “controversial” and that approval was required before she could be checked-in.

So what is an inhibited person? It’s not a term used by Australian agencies. But Dean Procter on Twitter directed me to an agency that does use it — the Department of Homeland Security. According to one of DHS’s operating manuals for airlines,

“Travelers receiving an inhibited response must be further vetted prior to receiving a boarding pass authorization. The response message returned will provide a contact number that must be called to determine if a resolution can be accomplished.”

That sounds exactly like what happened to Robinson. Another DHS document says:

“‘Inhibited status’, as defined in this rule, means the status of a passenger or non-traveling individual to whom TSA has instructed a covered aircraft operator or a covered airport operator not to issue a boarding pass or to provide access to the sterile area.”

In March, as part of the US government’s seemingly remorseless attempt to impose its laws on the rest of the world, the UK agreed to new rules that required airlines to provide the Department of Homeland Security with details of passengers even if they weren’t travelling to the United States, but to countries near the US, such as Canada, Mexico and Cuba.

Robinson, plainly, was going to none of those. But it raises an interesting scenario for when Robinson next seeks to travel to the US.

DFAT yesterday said it knew nothing of what happened. ABC journalist Jeff Waters last night contacted a spokesman for the UK Border Agency, who denied that they had stopped Robinson.

Which leaves the airline, Virgin. But the only circumstances in which an airline would stop a passenger in the manner Robinson was stopped is if she was not a citizen of the country she was flying to and there was a risk the airline would have to return her to her point of origin if she was refused entry, costing the airline money.

Plainly a government agency is either lying or knows far more than they are letting on.

But because of the tangled web of responsibility for international travel, it’s impossible to do more than speculate. Different agencies within government, different government, and private companies all have different but related functions. It’s a particularly egregious example of how governments can deflect responsibility and scrutiny because decision-making is outsourced into a nebulous mix of systems and separate decision-makers, leaving no one person or agency ultimately responsible. And international air travel has long since become a Kafkaesque mix of security theatre, institutionalised paranoia and irrational bureaucracy in which any semblance of logic is not merely dismissed but might even be considered a threat.

This outsourcing of responsibility enables governments and politicians in particular to operate with complete deniability. Ministers, who used to be considered responsible for what happened in their portfolios, can place their hands on their hearts and swear they know nothing, that they have sought advice and that it is nothing to do with them.

Meantime, lawyers, activists… hell, let’s call them what they are, troublemakers — get harassed without anyone with any authority having to front up and accept responsibility. It’s all part of the constant process of delegitimising dissent.