Sure there are many reasons why Chiyo herself would have done it and although Gaara is one of my favorite characters his death was not surprising nor was it upsetting in fact I was more upset when they created some lame ass jutsu so they could bring him back to life which is not something I agree with or think should be happening within the Naruto world (Orochimaru). Now you have to remember that this is Naruto and Kishi would not have brought him back to life unless he intended to use him in some capacity in the near or perhaps distant future, that being said the character of Gaara would be completely different if not absolutely useless without his abilities.

P.S. I wasn't flaming.