Hi Everyone,
Hoping for some expert advice on an unintentional skip-lag.

I purchased an open jaw Atlanta-Paris-Florence on the outbound, Madrid to JFK on the return in D1, on 006 stock.
The outbound is AF operated, the return is DL operated.

I've now learned that my meeting was moved from Florence to Paris, so I don't need the last leg (Paris-Florence), but I can keep the rest of my itinerary unchanged.
When I called Delta to ask about dropping the last leg, they told me that because the entire trip needed to be re-priced, it would cost me an additional $800 to drop the Paris-Florence leg of the trip.

I fly with carry-on only. So I was thinking I might just do the itinerary as is, deplane in Paris and skip the last leg.
But my question is: If I do this, how likely is it that Delta will cancel my return flight a week later from Madrid if I no show for the last outbound segment?
Does it help that the missed segment is AF and the return is DL?

Thanks!