A bit further in the article :

> Of course, the same device couldn't have been used in a standard cryptic crossword as word length breakup of solutions - (7, 7) vs (3, 4, 7) - would have given the game away.

Clinton would be 7 letters, Bob Dole is two words, 3 and 4 letters respectively.

I've never seen a crossword that does this, the ones I see just use the grid to show word breaks. However, I've also never seen a crossword that has one hint that cuts across a black square, like this one does. But I'm not an avid crossword puzzler.