Include a sessions folder?

It is Off by default and has never been On.

i meant change this:
$config['sess_driver'] = 'files';

to something like this
$config['sess_driver'] = NULL;

because - unless i'm missing something -  sessions works without any changes to the config.

Examples for what exactly? A directory path that is almost guaranteed to exist and be usable?

A couple of examples of what typically would be in $config['sess_save_path'] . It does not need to cover all cases. Just some samples to help people get started.