did you have time to try the above patch?

I've tested this patch above again with the latest develop and I can confirm it is not working.

When I delete a host without admin rights, the host is removed from the DB but the reports stay there with "orphan" host IDs and it breaks the UI reports screen with the error :

host_reports_url failed to generate from {:action=>"index", :controller=>"reports"} - you may have ambiguous routes, or you may need to supply additional parameters for this route. content_url has the following required parameters: ["hosts", :host_id, "reports"] - are they all satisfied? ActionView::TemplateError , 
(eval):17:in `host_reports_path' 
app/views/reports/_list.html.erb:19 
app/views/reports/_list.html.erb:16:in `each' 
app/views/reports/_list.html.erb:16 
app/views/reports/index.html.erb:3

I think this is fixed. When the destroy_reports permission is assigned, users can destroy/delete hosts without problems in 1.3.1.

Verified in Foreman 1.5 too, associated reports are getting destroyed even when the user only has the destroy_hosts permission and no report permissions.