Looks like an isolated incident. If they want you to have 2 cards, they could just mail them in one envelope
If they'd mail out a second card to every member, the not only had to pay the postage, printing the cards, envelopes and third party fees would add up to a lot more them 45K. That would be a concern. Otoh, if the third party made the mistake, they should be paying for it.
And Ibring my dog to the field, she is very well behaved, but not am AMA member and might pee on the grass.