Personally, this reeks of fraud, and I fail to see how it is legal in the first place. These consumers spend X dollars on Y products in advance, and HMV has the money, and the goods. Going into bankruptcy changes nothing. They have more assets than they are entitled to because of these gift cards.
In a just world, HMV would be required to honor these BEFORE paying any other debtors, and HMV sold these in good faith, and they were purchased in good faith.
I am disgusted.