Originally Posted by
Graciecatt
But if we wait until 24 hours before, how can we ensure we'll sit together just because we're on the same booking? What if there are not 2 seats available together?
If your daughter is very young (I believe 12 is the maximum limit), then BA will commit to seating you together one way or another. If she is older than that, you cannot be absolutely certain and indeed, there is always a small risk that no seats together are left, but depending on which cabin you are flying, this is not very likely: only a minority of people have status, and most people without status do not pay to pre-assign seats. What you could do is check the seat map 'as though' you were going to pay to see if many seats together are left. If at any point you see that there are only 2-3 pairs of seats left in your cabin, then you could make the decision to pay to be sure. If on the other hand there is plenty, then as
c-w-s mentions, theoretical seating should ensure that you are not split, and checking in as soon as check in opens will further guarantee you the best choice of seats.
There are no way to avoid the payment if you really want to pre-assign, have no Oneworld status, are not flying on a full fare ticket, and did not book a specific corporate rate some of which include free pre-assignment as a perk.