That was exactly my experience when I started using a Bold 9900 as my second phone in 2013. It's a rare AT&T associate who knows about BIS, but that's _fine_: You just have them reach inside their cookie jar full of old-timey SIM cards and get one for you. Go home, call the number on the SIM card holder to provision the phone number, and -- voila! -- your little BlackBerry icon just shows up. No special plan; no cajoling someone to throw a switch somewhere -- it just happens.