advance reader's copy

These are also called book proofs, galleys etc. I definitely have a dilemma with these books. I know these are printed by the publisher to be distributed at book conferences to anyone who really wants to read the book before making purchases for their businesses or for schools. I really do understand that issue. To give away a book might help sell the book.
My dilemma is this: my colleague acquired a few ARC s from Barnes and Noble, the book store. I didn't know this, its was not brought to my attention when the books came into the library. She sent the books to be catalogued into the collection. No problem yet! The books came back placed in circulation for the students to read. Still no problem, yet. We held our annual book fair and low and behold a couple of the ARCs are now a published book in the book fair to be sold to the students. I began to pull the ARCs from the collection. I placed the ARCs in what we call Honor Book collection. Now the issue is from my colleague why would I do that? I tried to explain that possibly there is a copyright issue with having the ARCs in the collection to be circulated when we have the purchased book on the shelves. The books are proofs, not paid for by anyone, so the author, publisher or even BN didn't get paid for the books and lastly it is a proof of the book which could have errors from simply spelling to who knows what kind of errorsor changes to the book.

So what is it, should these ARCs remain on the book shelves along with the purchased book? Is it a copyright infringement? I do know since BN gave the books away, the ARCs aren't on their book shelves to be sold! Need advice, it just doesn't seem fair to the author or publisher to have the ARCs on the shelf next to the purchased book. I would like to have authors or publishers add to this entry.