That is indeed the correct behavior; the express edition is intended to make all users an administrator.
However, we are thinking of adding a new "mode" for express edition that will behave more like you desire: unauthenticated users will be able to view most everything, and authenticated users will be administrators.
In the mean time, why don't you just request an enterprise trial key? We understand that it can take while to totally prove out, and of course we will work with you to extend the trial key and help you prove the capabilities.