DL spends $ Millions on sophisticated software to catch ticketing fraud of all kinds. Do this once and all that happens is that one or both tickets get cancelled and that might leave OP having to purchase the seat he needs, if there is still one available, at whatever price is then available.
Do this a couple of times and he will find his SM account closed and not having to worry about the GUC's clearing because he won't have any.
A D1 seat is a valuable commodity, but it's value can't be retained. Cost DL the revenue from one of those and the reaction won't be kind. This isn't one of those things where they let you kiss and make up.