If you ordered a later model BCM, to obtain features not currently available in your model-year, after installing the newer replacement BCM you will need to perform an RF Hub reset or replacement. This is required so that the RF learns the new details from the BCM. The RF hub is the module in the vehicle that the key fobs are registered and programmed to. So this kind of results in the RF hub not recognizing the key fobs, so the vehicle won't start.
This only happens if the BCM is not a replacement of a defunct one but when someone is trying to add features to an older vehicle.