Originally Posted by
gooselee
Authorized Users get their own pieces of plastic that allow them to charge to the same Amex account, but points for their charges still go to the MR balance of the primary cardholder.
That's right. The key additional piece of information is that the primary cardholder can transfer MR points to an airline or hotel account in the name of any cardholder on the account, whether they be primary (themselves) or an AU. All MR points end up in a single pool that the primary cardholder controls, and it doesn't matter from which card on the account the charges that earned the points came from, or to which AU's airline or hotel acct they go to.