We have journaled extensively in the past and at various stages information has been written that is not for some alts awareness, but we have always found that there are internal protections against reading it. If one tries to read it but the information is something that alt can't handle or is protected against for some reason the information can't get in. Either a switch happens or the alt 'rolls away' -i.e. can't physically look at the info. More recently we tried video communication for the first time, and we found the same thing - some alts simply can't watch the video entries of certain others.
Which is a good incidator for me that there are still secrets within our system and not everyone is privy to all the information yet.