This is the thing that I personally would ask JKR if given the opportunity:

If Hagrid had his wand snapped when he was expelled, why was Bellatrix's wand not snapped when she was sent to Azkaban? I can accept that other escapees might not have their own wands, Sirius might be using a family wand given that he can't just pop into Ollivander's and buy a new one. BUT in DH it is specifically mentioned that Hermione hates using Bellatrix's wand thinking about what the wand has done; killed Sirius and tortured Neville's parents. The torture was why she was sent to Azkaban, so we know it's her original wand.

So, any thoughts and theories on how she got it back? Has this question been asked of JKR?

I thought of it, too. Probably JKR just didn't think about that, and now we have a mistake in the books ._.

Oh, and I also noticed that when Collin Creevey was killed, it was told in the book that he probably sneaked back to the castle. But they also say that muggleborns didn't learn at Hogwarts, and Collin was a muggleborn!
Yes, JKR definately didn't think about that either.

There are other mistakes in there, the classrooms and offices seem to move about a bit for examples. I wouldn't call it a mistake as such, more of an inconsistancy. Perhaps the wands are stored in the Ministry somewhere and Lucius bribed someone to get it back?

Poor Colin He probably snuck back when Wood, Angelina, Cho and the other students who had left did. He had a coin after all.

I dunno. Maybe Hermione just assumed that it was still Bella's wand. Although that is unlike Hermione.

More likely is JK just sort of forgot about that little thing. Was five books ago after all.

It just seems like a big plot point to forget about, when you think about how much reference she makes to Hagrid's umberella.

Yeah. Then again, Hagrid managed to get all the pieces of his wand back, and they worked again. Also, he never actually used Dark Magic.

Maybe there's a way to remake wands that have been snapped, via Dark Magic, we're just never told about it?

Good point!

JK has already answered this one, she was told of this "mistake", and said it was not a mistake.
Both Colin and Dennis Creevey were members of Dumbledore's Army and Neville alerted all members by their coins, so He would have known that they were fighting for Hogwarts, so he returned and subsequently died.

R.I.P. Colin!


And on the Subject of Wands, perhaps some wands were kept by the Ministry guarded by Dementors and she was able to retrieve hers once the Dementors were turned.
Its highly unlike that her wand was snapped and then mended - as Ollivander said no wand can be repair(with the exception of the use of the Elder wand)