Joel,
ICM wants to route based upon valid real-time enterprise information; this is one of the reasons why there is a mechanism count Device Majority. No one would want ICM to make enterprise routing decisions on a small percentage of accurate information.
To your questions: if the count goes less than majority then the B side Router will bounce and attempt to restart. Without the majority count, the Central Controller service wont go active (i.e. Router B wont return).
/Jeff