Percy as Traitor?

[supermouse35]

No: HPFGUIDX 42991

There's been some talk on-list recently about the idea of either 
Neville or Seamus being a traitor in the later books.  I'm 
currently re-reading GoF and the following passage from the end of 
Chapter 27 caught my eye (p. 534 in the hardback US edition):

"Percy would never throw any of his family to the dementors," said 
Hermione severely.

"I don't know," said Ron.  "If he thought we were standing in the way 
of his career... Percy's really ambitious, you know..."

JKR isn't the type of writer to just throw a passage like this in for 
no reason.  So what do you think, is this foreshadowing?  Or is she 
tossing us another of her famous red herrings?

Gina