need quick answer, sorry for not searching
I don't think it matters much. It might be more of an issue if the same Amex account is transferring to loves of BA accts or it's a BA acct that's received transfers from lots of Amex accounts. I guess it might also depend what kind of awards you're booking with BA, how many of them, and for how many passengers.
If it's a one-time thing and you're not doing anything overly suspicious, you have nothing to worry about, especially if the passenger is the same as the BA accountholder.
