Bank shots, kick shots, carom shots, billiard shots, are not obvious and must be called, period. Being obvious to the shooter does not qualify as being obvious to the opponent of these 4 types of shots. Other shots are obvious and need not be called.
That assumes the shooting player is honest. Without a referee, the shot still goes to the shooter regardless if they call the pocket or not. In this case, the shooter admitted they didn't call the pocket. B wins period! Just ask Shane.
Lyn