You could always expose the fields and have results returned "If Contains: Enter Keyword Here". Nothing will get returned AND you'll have a nice user friendly instruction already entered in the text box.
I thought about that also. Then I would have to add a JS trigger to that field so that when they put the cursor there, that text goes away. To leave it there will be confusing for some users, especially those who won't know precisely how to remote it easily.
I suppose I will see which is easier then--edit the PHP or add a JS trigger.
Thanks