Long time lurker, first time poster.

I signed up for the Chase British Airways 100k miles promotion and booked a flight to Thailand on Cathay Pacific in May. I was considering cancelling this card before the next annual fee is charged at renewal, which is before my flight. Would this be grounds to cancel my itinerary? I don't think so, but just making sure. If not, here's my main concern:

Cathay Pacific says that I must bring the card I used to make the booking (I booked with this BA card) with me when I check in at the airport. Would they scan this, or just check it? If I cancel it and just keep the card on me until then, would this solve the issue?

Thanks!