Well BC is for M2 not for Kingdoms so we should probably discuss it in the MII MPC Guide
But! Here is my configuration for my BC preferences CFG file which I have set as 'Read Only':
[multiplayer]
playable = true
[hotseat]
autoresolve_battles = 0
disable_console = 1
disable_papal_elections = 1
save_prefs = 1
update_ai_camera = 0
validate_diplomacy = 1
My Medieval 2 preferences CFG file is also set as 'Read Only' and here are it's settings:
[hotseat]
autoresolve_battles = 0
disable_console = 1
disable_papal_elections = 1
passwords = 1
save_prefs = 1
update_ai_camera = 0
validate_diplomacy = 1