Make a User Selection rule and set it to "Active - All Lists - Search - Exact - in Last Name". Click "Show Query" and when the page reloads, the "Exact" has been changed to "<=.
Also, I did a search with all lowercase letters in the Last Name field, and it matched a last name in the database which was capitalized. I like this behavior but I question the help text on that screen that says "Searches are case sensitive" - it seemed that it was case insensitive.
