Never, that is correct. The law allows for defendants to choose to be enjoined, grants some leeway to the court, and sets forth exigent circumstances for joinder. However, any future defendant in a matter brought by EDIG (I don't think there are going to be any, and if there are they will not be represented by DM) would be well served by trying to remain separate to created cost challenges for the plaintiff.
As I said, I don't think it's going to make any difference to EDIG because I doubt there will be any more litigation, just as I doubt we will ever hear of Nunchi again, at least in terms of any sales or licenses. We'll continue to be spoon fed pablum about patent and TM applications and "progress" in those areas no doubt.
LL