Simple way to protect a page

My client has elected to use Aweber, to both provide a coupon code and redirect the person to a page in MODx that displays the coupon code.

I’ve taken care of the obvious:
- unchecked the "Show in Menu" and "Searchable" boxes
- added manually the pagename (page id# and FURL url) with disallow instruction to robots.txt

Is there any other way you would suggest I protect this page from being accessed?

Thanks!

Why don’t you check DocPassword snippet ?