Wikipedia even mentions it
Unless geopolitical changes play a role, players are generally not allowed to switch nationalities if they have made senior appearances for one FIFA-recognised country in competitive fixtures. Friendly match appearances do not commit a player to one country (though a player is usually able to switch to another national side only if he held the nationality of the second country at the time he represented his first choice national team);
Wiki isn't the be all and end all. FIFA rules are - but what they mean on that wiki page by 'competitive fixtures' is a match in a competition, be it qualifying or the finals of a competition.
The reason Durante's eligibilty was up in the air (aside from the stupid games he played for Sydney) was that he was on the bench for an Australian game in an official competition. (It was a qualifying match for the 2011 AFC Asian Cup NOT a friendly).
If you're still not convinced, explain this guy: http://en.wikipedia.org/wiki/Jeff_Cunningham
He played for Jamaica BEFORE getting US citizenship and subsequently playing for the USA. He could do this because he hadn't played for Jamaica in an official competition match.
FIFA eligibility has been reviewed many many times since 2001. The rules then are nowhere near the same now.
You also forgot to bold the other bit. I have copied and pasted it for you
"Friendly match appearances do not commit a player to one country (though a player is usually able to switch to another national side only if he held the nationality of the second country at the time he represented his first choice national team)"
When he played the friendly for NZ, he did not have eligibility for Japan. I'm not quite sure now clear you need it Wibble but I'm done with it. If you want to believe it, you do so. It makes no difference to me. You also failed to note the Article 17 as well so......