During some discussion with guildmates out of game on where everyone will go after Imperial City is released, a potential feature came to be imagined and slightly refined.

To access the Imperial City, all the necessary (home for now) keeps must be held, but once inside there is little to no incentive to hold those keeps as we can theoretically remain inside forever. And with this point came the topic of kicking factions once they lost the necessary keeps to stay inside. However kicking a faction once the keeps are lost seems unfair, as each player will have 10 or so seconds to wrap up whatever they are doing before being booted. That type of system would be all-in-all unfair, as all necessary keeps must then be held at all times to remain inside, and we all know how swiftly a keep can change hands.

ZOS mentioned that players can respawn in the sewers upon death, allowing them to continue exploring the city even without the necessary keeps to enter, albeit from the beginning. So the issue is making holding the keeps worth something without making it impossible to stay in the city for prolonged play times.

What if, then, when the necessary keeps are lost players inside the Imperial City cannot respawn at the sewer's entrance? Once the necessary keeps are lost the ability to enter and respawn 'via wayshrine' are lost, allowing those inside to continue their activities and for other factions to "kick them out" if they really try to. It becomes something of a survival game inside the Imperial City once the necessary keeps are lost. Keep in mind that players can still resurrect with soul gems.

This topic would not be complete without bringing in the districts, which serve as proxy keeps inside the Imperial City. Players should be able to respawn at held districts regardless of the keeps held outside. "Wouldn't they then become a substitute for the sewers spawn?" The simple answer is "no." From the information ZOS disclosed about the districts, they can be taken from other alliances, flipped in other words. And more importantly, every 10 to 15 minutes the daedra retake each district. The districts are not permanent spawn points like the sewers entrance.

This is the idea as far as it got refined in the conversation. I present it here on the forums to allow other people to discuss the feature, and to give it a little more attention.
Any feedback is welcome. Like it? Hate it? Think of a better way to implement it? Please, post it!