Originally Posted by
mtkeller
If you can book it all on one reservation, there's no problem with it. DL issued it as one ticket, so they can't come and charge you with fraudulent ticketing.
The issue in OP's case is that s/he wants to avoid the two-night stay requirement in the fare rule and thus needs two reservations. This is an attempt to circumvent the fare rule and thus technically a violation of the CoC.
Why? CoC applies to a single itinerary from A to B as ticketed. CoC doesn't spread itself across every itinerary you have booked with an airline. Two night stay doesn't mean you need to produce a hotel receipt showing two nights in a specific city to qualify, it simply means the return portion of this itinerary must occur two nights after the originating portion of the trip.
The downside to this is that if you miss one leg due to CX or other delay which causes you to miss the next leg of the other itinerary, you could get screwed badly. Because they are separate itineraries and the CoC doesn't extend itself across the two trips, you can't argue that you missed a flight because DL didn't get you there on time. For example, A1 becomes delayed 6 hours. You land in FLL at 1PM, 40 minutes after B1 took off. From DL's perspective, you just slept in and missed your B1 flight. The answer could be... "the next available seat to JFK is two days from now unless you are willing to pay a $150 change fee and the current fare of $834 for a total of $984".