I wouldn't think the airline would do that on purpose ... but who knows.

Allegedly Delta's computer system does rebooking automatically in such circumstances, and it starts with the highest elite levels/highest fares and works down from there in priority order, so if you were a regular schmoe with no elite status and a deep discount fare, you'd end up on the last flight, while if you're a Platinum on a Y fare, you're going to end up on the next available flight.