question about crookshanks

[Carol]

No: HPFGUIDX 185812

Carol earlier:
> >Carol, who wonders if Sirius Black would have been a little less
>lonely and depressed if Hermione had left Crookshanks with him in 12 GP

Jerri responded: 
> I feel that it might well have helped, which is why JKR couldn't
allow it to happen!

Carol responds:
Good point.

Jerri: 
> I certainly expected Crookshanks to play a more important role in
the final books, rather than just disappearing. <snip> of poor
Hedwig!)  Once I learned from Fantastic Beasts and JKR's interviews
and/or web site that Crookshanks, like Mrs. Figg's cats was part
Kneazle and that Kneazle's had all the wonderful attributes described
in FB, I felt sure that Crookshanks could be of substantial assistance
at some point.  Instead, his high point seems to have been in PoA. 

Carol again:
Me, too. (It's okay, List Elves! I do have something to contribute,
however small!)

Jerri:
> The "uncanny ability to detect unsavoury or suspicious characters"
could have been of great use at Godric's Hollow, for example. <snip>

Carol responds:
In retrospect, it's interesting that Crookshanks never hissed at Snape
 with his fur standing on end as he did with Scabbers. And his
anti-Scabbers reaction can't just be to Scabbers/Wormtail being an
Animagus or he would never have befriended Padfoot/Sirius, who was
also an Animagus. I take his nonreaction to Snape to mean that Snape,
for all his animosity toward Black and his friend, Lupin (also not
hissed at by Crookshanks), did not trigger Crookshanks's "Kneazle
sense"--IOW, Crookshanks didn't intuitively react to Snape as
"unsavoury or suspicious," a clue that perhaps should have signalled
that Snape, for all his unpleasantness, was a good guy.

But don't we at one point see Crookshanks in the same room (the
kitchen at 12 GP) with Mundungus Fletcher? Surely, Dung was an
"unsavoury or suspicious character," but Crookshanks, IIRC, has no
reaction to him.

Carol, wondering what would have happened if Crookshanks encountered
Crouch!Moody in HRH's presence and suspecting that his disguise might
have been revealed early (just as it would have been by the real
Moody's Sneakoscope if he hadn't disabled it)