This likely isn't the correct place for it, but why doesn't this game have a proper IC reasoning for the absence of characters when their player goes on a hiatus?

For example, a character who is very social and would never simply drop off for a week or more on his own from the network or missing very important plot events looks very strange gameplay and characterisation-wise.

In other games, there is the option they were "trapped in a forest" or something along those lines. Why is there nothing for Shibusen?