Sneakoscope question

[vmonte]

No: HPFGUIDX 95811

Sylvia wrote:
Many thanks, Steve, for coming up with a (I think) water-tight
explanation of why the sneakoscope went off when it did. I was
puzzled by the fact that both Scabbers and Lupin had been in the
carriage all along, without setting off the mechanism, but if
Scabbers had heard Lupin's name, it would naturally set him off into
panic-mode, thereby activating the Sneakoscope, which had remained
dormant while he was.
Incidentally, I'm convinced Lupin was awake all the time.
Eavesdroppping is too harsh a word. He was doing what DD had
presumably told him to do i.e. keeping an eye (albeit metaphorically)
on the kids, knowing that the Dementors would be arriving. Why else
was he travelling on the train. None of the other teachers do.

vmonte responds:
I think that Steve's explanation was on mark as well. Sylvia, I also 
agree that DD told Lupin to keep an eye on the kids.  :)