"Your Owl Will Find Me"

[Cindy C.]

No: HPFGUIDX 29839

I was musing a bit about owl post today.  So far, I've just sort of 
assumed that if anyone sends an owl to anyone in the wizarding world, 
the owl will find that person every time and deliver the message.

In PoA, Sirius tells Harry that if he needs to contact him, send a 
message and "your owl will find me."  I always assumed this just was 
Sirius' way of telling Harry not to worry that his owl can't find a 
person in hiding.

But maybe there's more to it.  Maybe what Sirius really means is "Now 
that we have a relationship and I know you have good cause to seek me 
out, I will allow your owl to find me."  In other words, perhaps in 
the wizarding world, an owl cannot find a wizard who does not wish to 
be found.  

This might explain some strange things about owl post.  Many people 
have wondered why Sirius is able to hide, because MoM ought to be 
able to just send him an owl and follow the owl to determine Sirius' 
location.  It might be because Sirius doesn't want any MoM owls to 
find him, so the owl wouldn't be able to.  Other people have wondered 
why Sirius never sent an owl to Lupin or Dumbledore or even Harry 
explaining his innocence.  Again, maybe they weren't receptive to an 
owl from Sirius, or at least Sirius believed they wouldn't be.  Also, 
if Harry is a big celebrity, one would think that he would receive 
unsolicited "fan mail" owls all of the time, but he doesn't.  Maybe 
that's because they are returned undelivered because Harry is not 
receptive to reading them.

OK.  There must be a huge, gaping hole in this theory.  What is it?

Cindy