Had a completely out of left field idea.

This would require some working with SAPP as well, however... what about an in-game reporting/admin calling system? A SAPP server owner can setup something where they put the XFire IDs of moderators/admins into a config file or something like that, and if you have HAC2 and XFire, you can type the /report command into the servers chat, which will then work both server and client side, where the server will send the XFire IDs of the listed moderators/admins to the clients HAC2, which will then communicate to the clients XFire to send a pre-written message to an online moderator via XFire to join the server at IP xxx.xxx.xxx.xxx:yyyy for a report against player New001 from player New002. Of course, a server can turn this feature on/off, but this may be something worth looking into. I've seen something similar to this before in different games, and I don't see why HAC2 couldn't make this possible with Halo and SAPP. Of course, you'd need flood protection as well, and maybe a server variable could be added where the message could only be sent after x amount of reports.

Also, is there eventually going to be something where a server owner can require players to have HAC2 when they join their server?