In theory it shouldn't, because each leg has its buckets of availability, and there's not competing with another airline that flies direct for the fare. But in practice I believe there have been rare occasions where a leg is available for award redemption only as part of a multi-leg trip.
actually, this happens often w/Delta because they used married segment logic. If you live in a hub, this can work out great.
Another useful case where hidden city ticketing can save on domestic award flights is AA's reduced mileage awards. If you can find availability with American (and that's a huge IF) and you have their Citi/Aviator card, then you could theoretically book a reduced mileage saver award that includes a segment from JFK-LAX for a reduced price if the final destination was MRY (and just get off at LAX if that was your final destination). I haven't tried this one myself, but I don't see a reason why it couldn't work