The value 0 for the setting means that the default access level for the content created inside the group will be private (only the person who created it can see it).

Elgg core doesn't have that feature by default, so it must have been added by some third-party plugin (most likely by group_tools).

Does it matter that some groups have different default access level? After all it can be changed when creating content.

If you were to remove the values manually from the database, how would you prevent it from getting saved there again?

Consistency matters for a UI.. People expect a certain behaviour across the whole site. My particular group of people are not very technology savvy and the less they need to touch the better. So I want defaults to be the most common use case (i.e. publish the object and send the notification). This is particularly important when the creator of an object does not get notification, someone could easily think the discussion or other object was notified to others and in fact it was not.

Its cool. I think I understand which combination of settings creates the entry. I think its a bug, but I believe its in group_tools. Need to do some more fiddling to isolate the conditions.

Register a plugin hook handler for the desired type:

https://github.com/Elgg/Elgg/blob/1.9/mod/blog/start.php#L41

And edit the title, body and/or summary in the handler:

https://github.com/Elgg/Elgg/blob/1.9/mod/blog/start.php#L248