The onward flights get cancelled out many hours after the no show of the first flight, usually via an end of day batch process. Assuming a one-way hidden city ticket, where boarding pass for segment 2 is obtainable via online check-in, then you would be able to fly segment 2. Everyone on Flyertalk just parrots the official rules and never answers the specific questions of how it actually works. See for yourself with a dummy refundable fare, online check-in day before, and look at your reservation still in tack at Delta.com 20 minutes before departure of segment 2.