The Delluminator always confused me. After its first name-change from Put-Outer to Delluminator, it was used as a tool to darken areas by absorbing the surrounding light. That is how Dumbledore and Moody used it.
Suddenly, we are introduced to a new use of it – some sort of guide that allowed Ron to hear them talking about him, and then enable him to apparate to where they were.
Is this something Dumbledore custom designed for Ron and just as a matter of style (#phineasnigellus) put it in the deluminator, or did the deluminator always have that function?
I heard from somebody (I think he saw it online, didn’t sound like his own!) that Dumbledore always used that to “spy” on Harry, which is how he knew – often without any rational explanation – where Harry had been and what he had done. [Think Book 2, where Harry is under the Invisibility Cloak in Hagrids shed, yet Dumbledore knows exactly where they are, and talks to them.]
This would enable him to listen to anything they said while mentioning his name. This theory, however, has many holes. Firstly, it would be a stupid way of designing that he could only hear when they said his name, because many conversations he would have wanted to hear he couldn’t, because they wouldn’t have mentioned his name.
Secondly, why would it only work when Harry mentioned his name – it would surely work when anybody in the world mentioned his name, which would surely be all the time! And if it were keyed in for Harry only, how does Hermione’s voice suddenly come up?
[This could be explained that the person closest to the heart of the owner would be heard; Harry was closest to Dumbledore, and Hermione was closest to Ron]
Thirdly, there are certainly things that happened while mentioning Dumbledore’s name that he didn’t know about. For example, Dumbledore’s Army – Dumbledore clearly didn’t know the name until he heard it, at which point he instantly came up with a plan. Another point would be where Harry tells Scrimgeour that he is Dumbledore’s man through and through, which Dumbledore didn’t know about until Harry told him after that.
I don’t buy that. But honestly, it seems like far-to-big a coincidence to have these two functions rolled into one!