If the dblog module is disabled, there is no way for a site administrator to know which IP address a particular entity was created from. For a fairly active site, it's arguable that dblog isn't really a great solution for determining an IP address either.
To solve this, I think the ban module (or possibly a new module) should do the following:
* Create a new table to store entity -> ip address mapping
* Display the IP address on entity view/edit pages
For sites requiring a strong audit trail for their content, this functionality would be useful as a standalone module as well. Ideally, we could write the IP tracking module and add it to core, make the ban module depend on it, and then tackle #1844992: Allow to ban an entity author's IP address through an action (or entity operation).