FOX85 is not really correct. While you can transfer points from an Amex MR account to someone else's frequent traveler account:

• This is not an official feature of the program - they could rescind the ability to do that.
• Consider the case where A and B both have MR accounts, but B wants to cancel their last Amex card. They might prefer to have Amex points in A's account, but they will have to use them in some way before B cancels their account, or lose them.

I had a weird experience about a year ago. My father, who had no Amex cards, got an Amex gold biz card, with me as an AU. Amex assigned his points to my MR account. That actually was quite alright with us, since the whole purpose of getting the card in the first place was to add to my account. But I have no idea how it happened. I once asked Amex at the time we opened a card in my wife's name if they would do the same thing, and they said no.