In Star Trek, everyone is so zealous about their "space" (such a big deal for huge amounts of nothing, it is planets that matter in any galactic strategy).

However, I wish that there was some respect for one's claimed terrritory in GC2. Specifically, I would like that once you claim a solar system all planets therein become yours, colonized or not, like it was in GC1. I just hate it when someone comes parachuting into a system in the middle of my empire, even to the point of dropping a game if it is an especially annoying interloper. This means I have to colonize meager planets like Mars early just to prevent it, detracting from my colonizing efforts elsewhere.

I know there are forms of dealing with this, mainly by subjecting the planet to intense influence, but that is a bother, it not always succeeds, and meanwhile I'm all frustrated by these invaders.