Wand allegiance.

[Carol]

No: HPFGUIDX 187262

Pippin:
> If wand function is supposed to be intuitive and/or mechanistic, then JKR failed. But  Ollivander consistently describes wands as subtle and sentient devices. That Voldemort doesn't  understand this leads to his downfall, so it seems to be a carefully thought-out part of the plot.  
> 
> Viewing the world as his personal toybox, Voldemort is not about to respect the opinions of a mere object. 
> 
> But clearly wands rely on their own interpretation of events, and it's up to them to decide whether or not an attack must be taken seriously. As each one is unique, they may not all respond the same way to the same circumstances. 
> 
> Hermione takes the Trio's expelliarmus attack on Snape  seriously in PoA, whereas Snape himself dismisses it. Fortunately for Snape, it seems his wand agreed with him. But notice that Sirius is careful not to attempt any powerful magic using Snape's wand except in concert with Lupin.
> 
Carol responds:

Hermione takes the Expelliarmus attack seriously because "we attacked a teacher!" and they could get into serious trouble (note that they don't--Snape says that they were deluded by Lupin). Her reaction has nothing to do with wand allegiance, which she knows nothing about (unless Ollivander told her, as he told Harry, that "the wand chooses the wizard."

IMO, that initial choice and the bond built up between the wand and the wizard as they learn together (mentioned by Ollivander in DH) is usually too strong to be severed by a mere Expelliarmus--unless one wizard actually defeats the other and takes his wand, in which case, the wand will usually yield to the will of the conquering wizard. For that reason, I don't think that the duels count. I agree that wands are sentient, and they know perfectly well that the DA is just practice. Had the disarmed wizards at the MoM (regardless of whether they were kids, Order members, or DEs) not recovered their own wands, however, the wands might have chosen to shift their allegiance. I'm not so sure that all of them would do so willingly, though. It's one thing for Draco's wand to shift allegiance to another kid with similar experience to Draco's or Wormtail's new wand, which hasn't had much time to develop a relationship with him to shift allegiance to Ron, and another for Bellatrix's wand to shift allegiance to whoever Disarmed her. I think the Elder Wand is the only one that simply considers force, and even it can change to a new master (Harry) when it understands the circumstances.

As for someone's remark that wands don't understand human language, I think that's wrong. They not only respond to spoken incantations (at least if they're spoken correctly with the proper arm or hand movements), they also respond, in the case of an experienced wizard with the power of concentration, to unspoken commands--to intent. Probably, like the Sorting Hat and even brooms, they have some sort of Legilimency. (Neville's broom can sense that he's afraid of it; Harry's Firebolt can sense the move he needs to make without any conscious thought on his part.)

Anyway, it's odd that Mr. Weasley tells Ginny not to trust an object that can think for itself if she can't see its brains but lets her have a wand. Maybe he knows intuitively about the bond between a witch or wizard and his or her wand and knows that wands (unless they're broken like Ron's in CoS or are involved in special circumstances like shared cores) don't normally act on their own. But they don't respond well to inexperienced wizards, either.

As to why Harry couldn't use the Snatcher's wand but Hermione could use Bellatrix's hostile one, I have no idea--unless Bellatrix's wand is so powerful that even a witch who hates her can use it (whereas the Snatcher's wand is rather weak, matching his low level of skill and power) or Hermione's skill and determination overrode her aversion to the wand, whereas Harry resented the Snatcher's wand and wanted his own back. I think the wand would *know* that he disliked it and be unwilling to perform for him.

Carol, noting that if wands are capable of allegiance and can choose to yield their will to a wizard's (or not), they must be sentient and capable of thought