Perhaps I'm just confused about what led to this decision. If so, I can sort of understand. Then, I think the policy needs reconsideration. Our library has policies and procedures very similar to those described by Kristine Brancolini and David Taylor. It seems to me a reserves operation is there to support instruction with both required and recommended books, especially for those students who aren't able to purchase everything.
Most students still buy their own books for the reasons already expressed in previous messages.
I wouldn't think publishers would be upset about libraries buying books for reserves that were not going to be purchased through the normal selection process.