Square Cash and Bluebird only Allows Visa and MasterCard “Debit” Cards

I have been experimenting with both Square Cash and Bluebird online reloads and found that both services only accept Visa and MasterCard “debit” cards.  No mention of why American Express or Discover cards are excluded.  I will check back in a month or so and see if that changes.  If anyone notices a change, please let me know.  I have some experiments to do.  I have tried (unsuccessfully) to use my Target Amex reloadable “debit” card but it wouldn’t work for either service.  However, if you have a cash back earning “debit” card, you can use it with both services.  I cannot reveal any more and am upholding the “Blogger’s Oath of Not Killing Deals”.  See Travel Blogger Buzz’s post today about Vanilla Reload Cards and Speedway Gas Stations.  Good night and only 26 days until my 24th birthday :)