At the end of the day, people play where they want to play. Forceing people to play somewhere they don't want to isen't going to help. All it'll do is leave you with less people logging and more angry people complaining about it.
People play in Liberty because its easier to find other people. If they'd wanted to play on thier own they'd play singleplayer. People also want to play with thier friends. If most people are already in Liberty, chances are that thier friends are too, thus they don't venture too far out.
Also, previous experience suggests if you start shouting at people to do something they don't want to do, they tell you to shut up and go away.
The funny thing is - since this thread started I have been flying about quiet systems trying to bump into people. Amazingly its worked better than any forum post I ever made. I suggest the whiners should at least try that. Worst case scenario - do some missions for a faction based out there. people will start thinking oh that system has people in it all the time lets go see what's there.