Just for the record, the charities that are processing AMEX cards have an additional fee to pay every month as well. Just as AMEX wants SB to keep on taking their card, they also want the charities to take their cards as well...
Just a thought.
Also, I got this from one the charities (Chabad) that sent me the email which I think is very impt to say:
**IMPORTANT: this program is not limited to donating to Chabad of xxxxx; you can spend your $25 credit at any participating Small Business Merchant. However we hope you choose to take this opportunity to join our important work in strengthening the Jewish community in the area.