BB dataplans are activated and controlled by VZW "through" RIM's carrier interfaces. RIM's systems have very much control of that BB in your pocket based on it's IMEI, PIN, etc. Why do you think that if "RIM" has a BIS email issue it affect everyone on ALL carriers? If RIM was to dissappear off the face of the earth tomorrow, your BB would stop working immediately regardless of the carrier still being in business.
