OpenRA

Surely, an observer doesn't send data to the battlefield, and therefore shouldn't cause lag? If it could be wired so that spectators aren't needed in ping checks, or whatever, so that spectators don't impact a game, that'd be great. However, this is all assuming that it isn't that way already.

I think that game net mechanics almost the same for spectators as for usual players. Spectator also can break the game using abort command.

Ideally spectators shouldn't cause lag.