the problem is that they have millions of dollars worth of value that could be at any time exchanged for goods/services
all the money left on gift cards can't be claimed as profit as it could eventually be turned in for goods, so they have millions of dollars that they're holding but can't claim as profit yet. it makes it impossible for them to do anything with the money they've taken in for the gift cards, and they end up having millions of dollars just sitting that they can't do anything with
http://biz.yahoo.com/rb/051209/column_lifting.html?.v=1
article on the issue.... oooh so boring......