An idea to spice up private instanced areas

[Shurrikhan]

If that's the case, then why make multiple instances for a room that will be devoid of players in a few months time?

Numerous MMOs will:

1. Start with a single lobby (or "channel").
2. At x number of players they make an additional lobby ("channel").
3. New players are sent to the lowest number channel available.
4. The server checks for the percentage open slots across the additional channels, and will typical prompt players with the option to merge back into the lowest open channel upon exceeding x% vacancy. This particular check varies between different MMOs, and others may allow direct access to channel switching and may list the population of each channel.

Others may also leave a given margin to allow prioritization in matching to a given lobby, such as by friends lists, level range, or quest progress range (especially where there is resultant phasing - changes to the world visible based on quest progression).