Last night, Bostonist received the unsettling news that the add-value machines at T stops weren't accepting credit or debit cards. On the last day of the month. As in, prime time for adding passes to their Charlie Cards. A tipper said that, after delivering the news, an MBTA employee yelped, "Don't kill the messenger!" The employee had reason to be concerned, as finding out one's card has been denied repeatedly makes people snippy. Real snippy.......