Simple example: use at to open a cmd prompt. You'll be surprised at what that prompt has access to. (hint: it's *more* than Administrator.) Disclaimer: I have not tested this as a pleb.
I saw this some months ago as a way to modify some certain Registry Keys in the locals Users area* that even Administrator can't even see, let alone change. Windows security is just so complex and poorly documented...**
Wade.
* not the local user's area, the local users area.
** to which I suspect people are going to disagree. :-)