While there aren't very many active admins left for GA tremulous (yes, I know it's our collective fault), there is an 'official' way of submitting incident reports.
http://www.gamearena.com.au/help/incident/
That is where you submit the incident report. Be sure to include a screenshot of the listplayers command to get their GUID, and Gamearena provides a means to upload your demo. This is all in the "READ ME!!!" post provided at the top of the forums.