More detail: https://github.com/gittip/www.gittip.com/issues/2666

tl;dr - 

82 users with tips set up to @sudoroom:
Error messages for the 15 users with "failing credit card on file":
"declined by card issuer" means the issuer thinks the transaction might be fraud (for any number of reasons). 

More information hopefully forthcoming as well... https://github.com/gittip/www.gittip.com/issues/2666#issuecomment-52997368

// Matt