If an American Express agent "shares" a list of ineligible charges, be sure to ask for the URL where this list is published, and ask why it is different than the list published in the card terms:
Eligible purchases to meet the Threshold Amount do NOT include fees or interest charges, purchases of traveler's checks, purchases or reloading of prepaid cards, purchases of gift cards, person-to-person payments, or purchases of other cash equivalents.
The cardholder agrees to the published terms, not to a secret list developed by a mid level manager.