As I still haven’t got around to saying much about the reasons for the Accord on Colonization limiting unapproved expansion due to not having found a case sufficiently interesting in its own right, let me sum up:
- Lots of tedious squabbles, border conflicts, and claim-jumping interfering with trade and economic development leading to the Great Powers having a collective case of “won’t you lot just shut the fuck up?”; and
- In severe cases, perfectly nice planets being damaged or ruined due to spite-addled jackasses thinking that if they don’t get to have it, no-one does. (And the collateral damage of the former, too.)