The ring of Loki can place (and with a Terra Shatterer, break) blocks within a WorldGuard region for which the player has got no permission to build in.

I like the relics very much but this is a big problem for Multiplayer. Another thing that is a bit of an issue is the fact that Prism doesn't record who placed/broke the extra blocks with the ring of Loki.

Thanks

asie said this in the IRC, if it helps at all:
daveydaves: i'd guess Vazkii needs to emit Forge events with a fake player