Shoutbox

I'm not sure if you can hide the tabs, but you can lock the preferences from being changed.

Just go to (on the main messenger window) Plus! > Preferences > Privacy Protection > Passwords > Enable preferences lock-down.

Hope that helps.

EDIT: Hmm, but that doesn't stop them from disabling logging from the chat window. Sorry

But this may still be a feature that can help in other situations if you didn't already know about it.