@Ghiest,
In the case of a Planetary league, such as NBT, there could be a valid reason for not fighting. NBT and its associated rule set and game modes have been developed over a period of 10 to 12 years. With NBT there is a "game within a game". There is the actual simulation of Battle Mech combat or as long time NBT folks say, "the Drop". Then there is the "back story" or all of the activities associated with the administration, economics, and planetary management of a major Inner Sphere house or Clan. While not fighting can result in a frustrating and boring evening of home entertainment, the longer term strategy could be served well by choosing not to fight. This would be the "live to fight another day" scenario. While Mercs and Pirate units have far less planetary management chores, to a lesser extent still have this "game within a game".
NBT is based on a no-respawn game play mode thus providing for more real world military tactics. For a given battle, once you are dead you are dead! No magical re-spawn occurs. While respawn game play modes are suitable for open public servers, some leagues, and provide for more gaming action, this game play mode does not lend itself to the administration of a given units resources and territory in the NBT Battletech universe.
When NBT evaluates the MW:LL MOD, the members of the league will determine if the game is suitable for the existing NBT rule set. If NBT would like to adopt the game for league play, then either the NBT rule set will need to change or an additional game play mode will need to be coded and integrated into the MW:LL MOD.
So it would behoove the NBT membership to anticipate a little coding work when this MOD is finally released.