Sim City - Cities of Tomorrow - Kick Players

@gatlin3456 - I agree - this is such an annoying problem! Unfortunately, the dev team never addressed the issue before they were disbanded and so this issue continues to plague the players (and clutter the servers with abandoned cities).

The main issue is that there are some country-specific add-ons and promotional items that were offered for a limited time that can no longer be had. If you have the Complete Edition, you should have most of the items, but not all. Not sure if the Nissan Leaf dlc automatically installs - I believe it's free - you may want to check to be sure you have it. There's also a Red Cross dlc (it was $10 regular price), which I don't see listed in the store anymore, so they may have inadvertently added to the list of things you can't get anymore. 

Quite a while ago, I listed all the items that could contribute in this post: Request to EA - Make Promo AddOns Available - Answer HQ If your abandoned cities were built by new-to-the-game players, I would suspect the country-specific items, as most new mayors should have the same base content that you have. I've seen recommendations to use a proxy or VPN to log in and get the country-specific additions. I've never tried it, but it seems like that could work. (There is an old guide on Reddit "How to get other DLCs outside of the country" - Google it if interested) I keep meaning to try it, but since I play offline, it's no longer an issue for me.

TLDR; There is no way to know what content exactly the other players had when they created the abandoned cities. Other than downloading any available content that you do not have from Origin, your only recourse is to make private regions and require others to ask for an invite to join. In that way, you can screen the mayors before they do a "once and done" city. 

I wish you luck - and Happy Building!