ORIGINAL: forsaken1111
I never claimed to speak for the majority, I just said I hope they do not implement this system. If you took offense, I apologize as none was intended.
Ok, mate. We're cool. [8D]
Like I said, we can't all agree with every system that's being suggested here. I take your point about not all aliens being averse to living next to a hostile empire, I just see the relationship +/- system as a good place to determine that. A colony on the border of a hostile empire would be first in the firing line if a war broke out so some unrest could be simulated.
To back up your point, there are of course some examples from Star Trek. You could take the Maquis as an example of a people who want to live on the Cardassian border and are happy there and will not allow the Federation to give their homes to the Carddies. There was also an episode of TNG where a colony of Native Americans were happy to stay in there homes and refused to leave, even as the Cardassians moved in next door.
I don't think I'm making generalistions nor am I proposing a magical barrier. I probably should have gone into more detail about the parameters that determine whether or not a race could colonise though.
Racial traits like aggression and friendliness could play a part in calculating whether or not the race will colonise in the area. So an aggressive race would have more success than a passive one, because their colonists have no fear of living on the border of another empire. A passive race that is also unfriendly may not have such luck colonising, because their colonists don't like anyone else and they don't have the aggressive nature to succeed in such circumstances.
So it's not a magical wall. It simulates an area of influence around a colony that has a realistic effect on the minds of other empire's colonists.