Your questions are somewhat confusing, because you seem to state a number of different problems that you want to solve:
- which students are copying?
- how to do a checkout without a working copy?
- can you just copy the .svn folder of a working copy some place else? (And expect what to work, exactly?)
I think your first question is bigger than this mailing list, and I don't see how Subversion can help you solve that problem.
Your second question doesn't make sense to me, insofar as I don't understand what you mean by a working copy without a checkout? Do you mean you want person A to checkout, and B uses a working copy? Or do you mean you want a checkout at one point in time, and then later use of the same working copy when the server is not available?
For your third question, I have a suspicion you'll be unsatisfied trying that, as the first thing you'll need to do is an "svn revert -R ." to restore the missing files, which will effective amount to having a clean checkout.