personally, I've kept myself out of this as much as possible, but I just can't any more. in dealing with this particular topic, only one form of DRM should exist for any mod for minecraft:
Not allowing the mod/game to load at all and printing it on screen that it is not properly signed with a link on where to get a properly signed version. This can be directly implemented in forge/fml and I believe something close already exists.
Under no circumstances should any mod author ever include code that would break a users world because it's not a "proper" copy, lack of permission, or whatever. Most regular users don't have a clue and just click play.
This also would include code to stop the game from loading because another mod is also loading or changing a mechanic that the author doesn't like. It is the end-users choice if they want to play with said mods installed.
As far as cross mod wars, slowpoke has given the solution as far as modpack distribution. If you don't want your mod distributed with another mod, just say so. Before giving permission, even blanket permissions, state this.
As far as anything that has already happened, they are done and over with and not needed to be brought up. Move on to a (hopefully) better future for mods and the community as a whole instead of arguing the same exact thing post after post.