If you do give the number AT check-in, do they enter the number for the entire itinerary or *just* that particular flight?

Celestar

I tried this with CP and it ended to be a costly problem. Gave them my AA number on one CP outbound leg and got the miles for it. On the inbound, I asked the gate agent to use my BA number and the BP was printed with my BA number on it. What I ended up getting was miles to the AA account only. Had to take another weekend to get the CP flight on my BA account.