Not sure if this is a duplicate issue. I did a quick search and couldn't find anything.
Problem/Motivation
As a administrator, the user should be notified of if mod_rewrite is not enabled. Otherwise, functionality like ajax and or some site functionality is broken.
Proposed resolution
Place in the status report in the admin section (/admin/reports/status) that provides a warning that mod_rewrite is not enabled and the administrator should turn on mod_rewrite in order for clean urls to work.