If you really must add this feature: open EWRatendo_ControllerPublic_ThreadFair enough, but I couldn't twist you arm to put it in as an option????
Not right away or anything of course though as I know you've got heaps of other projects on the go.
if ($response instanceof XenForo_ControllerResponse_View && $options->EWRatendo_eventforum == $response->params['forum']['node_id'])
if ($response instanceof XenForo_ControllerResponse_View)
Then simply make your event thread, and then move it to a different forum...
This will add an extra query to your threads.