I added a simple hook to our settings file that prevents deletion of the
main page on any Wikimedia wiki. Thankfully, it does not require flooding
the database with 3.8 million edits (5000 edits times 763 wikis).
The hook prevents display of the deletion confirmation page. If the
confirmation page is displayed, then you can delete the page. Do not
believe anyone who tells you otherwise.
-- Tim Starling