Voldemort spy? - Not Bertha

[Hagrid]

No: HPFGUIDX 131917

---  "Beth Currie" <lists...> wrote:

> Voldemort has just risen and is telling the Death Eaters 
> how he devised his plan to get at Harry:
> > 
> < "Dumbledore invoked an ancient magic, to ensure the boy's 
> protection as long as he is in his relations' care.  Not even I
> can touch him there....then, of course, there was the Quidditch 
> World Cup....I thought his protection might be weaker there, 
> away from his relations and Dumbledore, but I was not yet strong 
> enough to attempt kidnap in the midst of ...Ministry wizards." 
> >
> 
> What jumped out at me on this re-read was, how could Voldemort 
know that
> Harry was going to attend the Quidditch World Cup?  
> Beth

aussie:
When Harry left the Dursleys in COS in the flying car, DD sent owl 
mail to Harry to the Weasleys.

Umbridge didn't send the Dementors to Little Whinging until Harry 
was away from 4 Privot and down at the park.

Owl posts found Harry in PS/SS no matter where Vernon took the 
family.

Hagrid could go to pick up Harry on ... well, wherever that rock was.

My point is, just as the Weasleys have a clock to follow the 
movements of the family members, does Harry have something that can 
track him?

It was probably in place after DD passed him to the Dursleys, so 
after Peter disappeared from the OOTP

Not just anyone could use that tracking/spy devise. Snape couldn't 
locate Harry for hours when he flew to MOM in OOTP.

Any thoughts on this?
aussie
Is there something that can locate