Currently, when a wiki is closed (regardless of the way, i.e. script, ManageWiki) there is only one sitenotice that appears which says "This wiki has been closed because there have been no edits or or logs made within the last 60 days.".
In some cases, wikis are closed for other reasons via ManageWiki, and it can be confusing for the sitenotice to claim that they were closed due to inactivity. The same goes with private wikis, which cannot be adopted, but the sitenotice claims that they can be.
Therefore, we should have 3 sitenotices for the different instances (1: script closes for inactivity, 2: wiki closed via ManageWiki, 3: wiki closed with script; private). (and then of course if the closed wiki also becomes inactive the script will change the message again)