I tried to list one of these as a giveaway a couple of years ago and I was told that AS companion codes cannot be listed or requested on CC due to the fact that money would need to change hands and that is not allowed (vs a trade). This is because the booking must be paid for by the companion code holder if s/he is not one of the travellers, which they obviously would not be in this case. So the giftee would need to send actual money to the cc holder to pay for the flights which is not permitted on the forum. That’s what I was told.