Twenty something years ago my friends and I wasted days and nights playing civ. I tried it recently. I just keep getting annoyed by lack of cultural borders. I can't stand that someone is able to sneak up and build a town two steps from mine, hindering it's development. so, no. I don'g go below 3 any more.
units can't walk passed units, so strategically placing your units, creating a border, will stop that.