This is the current rule: Anyone may join any GM-controlled faction, at any time.
The original intend of this rule was to provide new players a spot to join in the game, and they wouldn't be left too far behind.
But it has its drawbacks... and people can exploit this system quite easily.
Example:
The goal of the game is to get 100 regions.
If a GM-controlled faction happens to be in the lead (lets say, it has 98 regions) it is theoretically possible for another player with only 50 regions to immediately switch to the bigger faction. So a person can go from last place, to the top of the chart. Not very sportsmanlike, and not very fair.
Of course, that is only my opinion.
This game is about
YOU, the player. So I would like
YOU to vote on the following proposals... (see below)