Should a lawprof let students read the Teacher's Manual for the casebook?

It would never have occurred to me to consider saying yes to a student who wanted to read the Teacher's Manual, but a colleague of mine is taking the request seriously. I received this email via faculty email list (and have permission to print it here):

I am sitting on an email request from a student who wishes to obtain info so that she can acquire a copy to the Teacher's Manual for our CivPro I casebook, and I am looking for input as to how to respond. The book contains a number of problems, and she says it would be helpful to check her answers. I agree. But we do much of this in class — and my fear is that students would not attempt to figure out the answers — but simply look them up, thus defeating the whole purpose. (And I do recommend supplementary materials which gives them more and better problems — as well as much better answers geared towards to students — not class instructors.) So I am learning towards saying no — but I am troubled by denying access to educational materials to a student who sees benefit in using them.

Why is anything readable off limits to a student who wants to learn?