Yeez, that is indeed very sour ....
Very shortsighted and not creating a delightful ending.
Especially if you are a repeat guest.
Admittingly my experience at Accor's lounges are limited,
But over at IHG's lounges, as Royal Ambassador
i tend to email in advance + mention at checkin again that i will be having late checkout,
and wish to remain to wait in the Club Lounge as i still need to wait before going to the airport.
Usually with advance warning this is no problem and i can still enjoy the F&B.