Add a 'report' button to the server browser that when clicked will pre-populate a form with:

1.server name
2.server ip
3.server provider

and have a text area for the reporter to detail their reason for reporting the server and obviously a submit button. Optionally fields for the reporters steamid/email could be included so the reporter feels 'in the loop.'

On hitting submit the report should be sent to the sp, the reporter (optionally) and bi. The sp can then act on the report.