I think this is the most valid response, as it doesn't even require that the head eagle necessarily be so easily corruptible. The whole plan could have been ruled out by Gandalf simply because he was worried the head eagle might be tempted by the ring.

What if you don't tell the eagles on the mission what's up? Even if corruptible, it would take at least some time for them to figure out what's going on and which of the hobbitses they are carrying has the ring.

The Eagles seem very picky about when they help and who they're helping. I highly doubt they would do such a deed without Gandalf letting them in on the full story.

Well, you can tell some Eagles that "there is a very important mission to go on with Gandalf, and we need some eagles who don't know why we're going on the mission."

Like, you could have the Army move a box of stuff for you, and tell the army, but still have none of the soldiers know what's in the box.

Care to elaborate? That possibility is discussed in the article, why do you think OP is wrong?

Ok, I'm sorry, you got me, I cannot give an as detailed analysis as the article's author. I just didn't want the books to become irrelevant by making the journey pointless :'(

Wasn't Boromir influenced by just being around the ring?

How does a giant eagle physically put on a tiny ring

The ring resizes to fit its bearer's finger.

The ring can change size http://www.thetolkienforum.com/archive/index.php/t-5856.html